
Bulletin No. 322 


f A, Economic Geology, 103 
1 \ B, Descriptive Geology, 127 


DEPARTS IK XT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

V GEORGE OTI9 SMITH. Director V 


GEOLOGY AND OIL RESOURCES 


OF THE 


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JJLIC 


SANTA BARBARA COUNTY 
CALIFORNIA 


RALPH ARNOLD and ROBERT ANDERSON 




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WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1907 

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Bulletin No. 322 


SpHpo / A ' Economic Geology, 103 
‘ \ B, Descriptive Geology, 127 





DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

t 

GEORGE OTIS SMITH. Director 


*23 



OF THE 

SANTA MARIA OIL DISTRICT 

SANTA BARBARA COUNTY 
CALIFORNIA 



WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1907 

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CONTENTS. 


Page. 

Introduction. 9 

Purpose of this report. 9 

Acknowledgments. 10 

Previous knowledge of the geology. 10 

Early history of the district.. 11 

Geography and topography. 15 

Location. 15 

Definitions of place names. 15 

Relief. 16 

General statement. 16 

San Rafael Mountains. IT 

Santa Ynez Mountains. 18 

Santa Maria Valley. 19 

Casmalia Hills. 19 

Solomon Hills. 20 

Los Alamos Valley. 21 

Purisima Hills. 21 

Burton Mesa. 22' 

Santa Ynez Valley and Santa Rita Hills. 23 

Terraced coast. 23 

General topographic features..’. 24 

Drainage and rainfall. 25 

Climate and vegetation. 26 

Geology. 26 

Sedimentary formations. 26 

General statement. 26 

Franciscan formation (Jurassic). 27 

Knoxville formation (lower Cretaceous). 28 

Pre-Monterey rocks. 28 

Tejon, Sespe, and Vaqueros formations, undifferentiated (Eocene- 

Miocene). j .. 29 

General statement. 29 

Lithologic character. 30 

Structure and thickness. 31 

Age and fossils. 31 

Monterey shale (middle Miocene). 33 

General statement.,. 33 

Lower division. 34 

Upper division. 36 

Diatomaceous earth deposits. 38 

Composition of the Monterey shale. 39 

Material of shale. 39 

Microscopic appearance. 43 

Chemical composition. 44 

Alteration. 45 


3 















































4 CONTENTS. 

Geology—Continued. Page. 

Sedimentary formations—Continued. 

* Monterey shale, (middle Miocene)—Continued. 

Structure and thickness. 47 

Evidence of age.'. 47 

Metamorphism of the shale by combustion. 48 

Localities where the shale is at present burning. 48 

Typical occurrences of burnt shale. 49 

Depth to which alteration has extended. 49 

Lithologic character of burnt shale. 50 

Cause of the alteration^. 51 

Range in time of the phenomenon. 52 

Fernando formation (Miocene-Pliocene-Pleistocene). 52 

General statement. 52 

Lithologic character. 54 

Structure. 56 

Distribution. 57 

Evidence of age. 57 

Quaternary. 60 

General statement. 60 

Terrace deposits. 60 

General description. 60 

Lithologic character. 61 

Origin. 63 

Dune sand. 63 

Alluvium. 64 

Igneous rocks. 64 

General statement. 64 

Igneous rocks of pre-Monterey age.. 64 

Igneous rocks intruding the Monterey. 65 

Geologic history.,... 66 

Earliest periods. 66 

Eocene period... 66 

Lower Miocene period. 67 

Middle Miocene period. 67 

Late Tertiary and early Quaternary period. 69 

Main Quaternary period. 70 

Structure and conditions affecting the presence of oil. 71 

The anticlinal theory. 71 

Accumulation of oil in the Santa Maria district. 72 

Indications of oil. 74 

General structural considerations. 75 

Detailed discussion of structure. 75 

\ 

Region of the San Rafael Mountains. 76 

Areas of rocks older than the Monterey. 76 

Areas of Monterey and later formations. 76 

Folds.*.. 76 

Faults. 77 

Evidences of petroleum. 78 

Conclusions regarding future development. 79 

Region of Santa Ynez Mountains.80 

Area south of Lompoc. 80 

Area of Santa Rita Hills. 80 

Main portion of the Santa Ynez Range. 81 





















































CONTENTS. 


5 


Structure and conditions affecting the presence of oil—Continued. Page. 

Detailed discussion of structure—Continued. 

Region between San Rafael and Santa Ynez Mountains. 81 

Casmalia Hills and San Antonio Terrace. 81 

Burton Mesa. 83 

Purisima Hills. 84 

Folds.'. 84 

Faults and asphalt deposits. 85 

Conclusions regarding future development. 86 

Area around Santa Ynez. 86 

Solomon Hills and area north of Los Olivos. 87 

General features. 87 

Mount Solomon and associated anticlines. 87 

Structure. 87 

Asphaltum deposits. 88 

Conclusions regarding future development. 88 

Gato Ridge anticline. 88 

Structure... 88 

Evidences of petroleum. 89 

Conclusions regarding future development. 90 

La Zaca Creek-Lisque Creek anticline. 90 

Structure. 90 

Conclusions regarding future development. 91 

Summary of conclusions regarding future development. 91 

Details of the developed territory. 92 

Definition of fields. 92 

Santa Maria field. 92 

Contour map. 92 

What it shows. 92 

Basis of contour map. 92 

Difficulties of preparation. 93 

The wells.<•. 93 

Areas discussed. 93 

Oil zones. 93 

Hall-Hobbs-Rice ranch area. 94 

Location and structure. 94 

Geology of the wells. 94 

Product. 95 

Pinal-Fox-Hobbs area. 96 

Location and structure.. 96 

Geology of the wells. 96 

Product. 97 

Pinal-Folsom-Santa Maria Oil and Gas-Escolle area. 98 

Location and structure. 98 

Geology of the wells. 98 

Product. 99 

Hartnell-Brookshire area. 99 

Location and structure. 99 

Geology of the wells. 100 

Product. 101 

Graciosa-Western Union area*. 101 

Location and structure. 101 

Geology of the wfdls. 102 

Product... 102 






















































6 


CONTENTS. 


Details of the developed territory—Continued. Page. 

Santa Maria field—Continued. 

The wells—Continued. 

Eastern group of Western Union wells. 103 

Location and structure. 103 

Geology of the wells. 103 

Product.:. 103 

Lompoc field. 104 

Location. 104 

Structure. 104 

Geology... 106 

General statement. 106 

Burnt shale. 106 

Oil zones. 106 

The oil. 107 

Production. 107 

Arroyo Grande field._•. 107 

Location. 107 

Geology. 107 

Structure. 108 

Occurrence of the oil. 108 

Conclusions regarding future development. 108 

Huasna field. 109 

Oil of the Santa Maria district. 109 

Origin. 109 

Physical properties. 113 

General statement. 113 

Color and odor. 114 

Gravity. 114 

Viscosity. 114 

Chemical properties. 114 

Associated hydrocarbons. 118 

Natural gas. 118 

Asphalt. 118 

Technology of production and utilization. 119 

Oil companies of the Santa Maria district. 119 

Well drilling. 120 

Production... 120 

Storage capacity. 121 

Transportation facilities. 121 

Refineries. 122 

Utilization of the oil. 122 

Resume.'. 122 

Plates. 125 

Index. 157 












































ILLUSTRATIONS. 


Page, 

Plate I. Preliminary geologic and structural map of the Santa Maria district. Pocket 
II: Columnar geologic section of the Lompoc and Guadalupe quadran¬ 
gles. 26 

III. A, View of characteristic exposure of volcanic ash on Cuyama Piver; 

B, View of flinty Monterey shale on Sisquoc River. 34 

IV. A, View of characteristic exposure of diatomaceous shale north of 

Casmalia; B, View showing in detail weathering of diatomaceous 

shale. 36 

V. A, Typical specimen of diatomaceous shale; B , A similar shale after 

metamorphism by burning.:. 36 

VI. A, View of upper Fernando gravel, east of Figueroa Creek; B, View 

of sharp folds in Monterey shale north of Zaca Lake. 46 

VII. Geologic sections across Guadalupe and Lompoc quadrangles. 74 

VIII. A, View of Alcatraz asphalt mine, east of Sisquoc; B, View of Mio- 

cene-Pleistocene unconformity northeast of Casmalia. 78 

IX. A, B, Panorama of monocline in Monterey shale northwest of Cas¬ 
malia; C, D, View looking north at Graciosa and Western Union 

wells. 80 

X. Sketch contour map of the Santa Maria oil field. 92 

XI. A, View of Fernando brea deposit overlying Monterey shale, Gra¬ 
ciosa Ridge; B, View of saddle in Monterey, Fernando, and Pleis¬ 
tocene beds near Hartnell well No. 1. 98 

XII.* Tejon (Eocene) fossils. 126 

XIII. Knoxville (Cretaceous) and Tejon (Eocene) fossils. 128 

XIV. Tejon (Eocene) Pelecypoda. 130 

XV. Vaqueros (lower Miocene) fossils. 132 

XVI. Vaqueros (lower Miocene) fossils. 134 

XVII. Vaqueros (lower Miocene) Pelecypoda and Brachiopoda. 136 

XVIII. Vaqueros (lower Miocene) Pelecypoda. 138 

XIX. Monterey (middle Miocene) diatoms. 140 

XX. Monterey (middle Miocene) diatoms. 142 

XXI. Fernando (Pliocene) Gasteropoda. 144 

XXII. Fernando (Pliocene) fossils. 146 

XXIII. Fernando (Pliocene) fossils. 148 

XXIV. Fernando (Pliocene) fossils. 150 

XXV. Fernando (Pliocene) pectens. 152 

XXVI/ Fernando (Pliocene) pecten. 154 






























GEOLOGY AND OIL RESOURCES OF THE 
SANTA MARIA OIL DISTRICT, SANTA 
BARBARA COUNTY, CAL. 


By Ralph Arnold and Robert Anderson. 


INTRODUCTION. 

PURPOSE OF THIS REPORT. 

During the last three years the region near the Pacific coast in the 
northern part of Santa Barbara County, Cal., has shown promise of 
becoming one of the most productive oil fields of the West, if not of 
the whole United States. The developed fields lie on the low, rolling 
hills between the Santa Maria and Lompoc valleys, where the oil has 
accumulated in great abundance in the Monterey shale, of middle 
Tertiary age, which underlies this region. The lightness of the oil, 
which averages from 25° to 27° Baume, and the great productiveness 
of the wells, which yield as high as 3,000 barrels a day, with an 
average of 300 to 400 barrels, arb among the features for which the 
district has become noted. Large areas in the same general region 
as the productive fields have been known for some time to be analo¬ 
gous, so far as surface evidence went, to the proved territory, and it 
was thought that geologic investigations of the region might furnish 
valuable information and aid in the extension of developments. 
Accordingly, with the purpose of studying the occurrence of the oil, 
the extent and structure of the oil-bearing formations, and their rela¬ 
tions to associated formations, the writers carried on the field work 
leading to the present report during the summer and autumn of 
1906. The geology of the region covered by the accompanying geo¬ 
logic map (PI. I, in pocket) has not been completely studied in all 
parts. Between the San Rafael and Santa Ynez ranges it has been 
worked with considerable detail, but the mapping of the mountainous 
regions has been more in the nature of a reconnaissance outside of 
the areas of the Monterey formation. 

A preliminary paper containing the features of this report most 
immediately pertinent to the oil developments and an outline map 
has been published as Bulletin No. 317 of the United States Geolog¬ 
ical Survey. 


9 




10 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


ACKNOWLEDGMENTS. 

Mr. H. R. Johnson covered the territory northeast of the Santa 
Maria Valley, and the map and notes concerning that region are 
largely the result of his work. Dr. H. W. Fairbanks® is quoted on 
the geology of Point Sal. 

The writers are greatly indebted to Mr. F. J. Keeley and Prof. C. S. 
Boyer, of Philadelphia, and to Dr. Albert Mann, of the United States 
Department of Agriculture, for information concerning diatoms and 
their relation to the origin of the oil. Acknowledgments are also due 
to Messrs. E. C. Sullivan, W. T. Schaller, and George Steiger for 
making analyses of the Monterey shale. The analyses of oil on 
pages 115-117 were made by H. N. Cooper and published by the Cali¬ 
fornia State Mining Bureau in its Bulletins Nos. 31 and 32. The 
indebtedness of the writers to Mr. Cooper and to the mining bureau 
for this information is hereby acknowledged. 

Without the assistance of the operators in the developed field that 
part of the report which relates to the geology of the wells, produc¬ 
tion, and other technical data would have been an impossibility, and 
the writers therefore wish to acknowledge their indebtedness to the 
officers and managers of the different oil companies for their hearty 
cooperation and support. Thanks are due more particularly to Mr. 
W. W. Orcutt, geologist of the Union Oil Company; Messrs. J. F. 
Goodwin and F. J. Burns, of the Pinal and Brookshire oil companies; 
Judge John D. Bicknell and Mr. Morris Albee, president and secre¬ 
tary, respectively, of the Western Union Oil Company; Mr. Adolph 
Phillips, of the Graciosa Oil Company; Mr. W. O. Maxwell, of the 
Recruit Oil Company; Mr. Charles Off, of the Rice Ranch Oil Com¬ 
pany; Mr. E. E. Henderson, of the Palmer Oil Company; Mr. F. D. 
Hall, of the Hall & Hall Oil Company; Mr. W. A. Irwin, of the Clare¬ 
mont Oil Company; Capt. N. P. Batchelder, of the Los Alamos Oil 
and Development Company; Mr. Frank M. Anderson, geologist of the 
Southern Pacific Company; Mr. William Yanderhurst, of the Todos 
Santos Oil Company; Mr. D. G. Scofield, vice-president of the Stand¬ 
ard Oil Company, and many others whose assist ance has added mate¬ 
rially to the value of this report. 

PREVIOUS KNOWLEDGE OF THE GEOLOGY. 

Little attention has been given heretofore to the geology of the 
Santa Maria district. The earliest work was done by Thomas Anti¬ 
sell, with the assistance of observations by Albert Id. Campbell, in 
the course of the explorations and surveys for the Pacific Railroad 


a The geology of Point Sal: Bull. Dept. Geol., Univ. California, vol. 2, 1896, pp. 1-92. 




INTRODUCTION. 


11 


in the early fifties. a In the report on this work the larger topo¬ 
graphic features were well described, the presence of asphaltic rocks 
was briefly noted, and the Tertiary age of most of the sedimentary 
rocks was recognized, but the structural features and the relations of 
the rocks were in the main misinterpreted. 

During the course of the geological survey of California by J. D. 
Whitney a hasty reconnaissance was made of a part of this region . 6 
He says in his report: 

The region to the west of the San Rafael Range, between the Santa Ynez and Cuya- 
mas rivers, was cursorily examined by our party. * * * The region is occupied 
by hills of moderate height. No metamorphic rock was seen; but pebbles of serpen¬ 
tine and metamorphic sandstone were noticed, especially for 3 or 4 miles north 
of Alamo Pintado. * * * These hills were covered with gravel derived from the 
bituminous slates. At times, especially near the Santa Maria River, the hills were 
capped by a modern horizontal deposit (post-Pliocene?). The underlying rock, 
when seen, was the bituminous slate, sometimes dipping to the north and sometimes 
to the south. 

Near Foxen’s, on the south side of the valley, there were hills of nearly horizontal 
strata from 200 to 300 feet high, the north slopes of which were very steep, usually 
about 35°. Beneath the soft sandstone, which made up the principal part of these 
hills, was a stratum of infusorial rock resembling chalk in appearance, exceedingly 
light, its specific gravity not being more than 0.6 or 0.7; the thickness of this stratum 
was over 20 feet. The age of this formation is not yet definitely ascertained. 

North of the valley, at Foxen’s, the bituminous slate occurs with a high dip to the 
north, and asphaltum is found in several localities near. In places the slates are 
altered and silicified, sometimes resembling semiopal in appearance, the finest lami- 
nse of the original structure being preserved. 

So far as the writers are aware no further investigation of the geol¬ 
ogy of the region was made until H. W. Fairbanks made examina¬ 
tions of portions of the Coast Ranges and reported on them for the 
State mining bureau in 1894. In his paper on the “ Geology of 
northern Ventura, Santa Barbara, San Luis Obispo, Monterey, and 
San Benito counties” reference is made c to the region under discus¬ 
sion, especially to the Santa Ynez Mountains. Regarding the Santa 
Ynez Range he says: “It is formed, so far as is known, of Miocene 
rocks exclusively.” And again: 

There can be no doubt that the main portion of the Santa Ynez Range is Miocene 
with a general anticlinal structure, well shown in the San Marcos Pass. The center 
of the anticlinal is not generally the highest portion of the range, but lies on the east¬ 
ern slope. The normal type of anticlinal structure is also marked by an east and west 
compression, producing features, however, of secondary importance. 

As viewed from the south at various points the range consists of heavy-bedded sand¬ 
stone, dipping at a high angle to the south. * * * At the western end, in the vicin¬ 
ity of Point Arguello, no anticlinal structure is apparent, but steeply inclined and 
broken strata. Asphaltum is found in many places near the sea from Point Arguello 
to Ventura County. 

a Pacific R. R. Repts., vol. 7, 1857, Chaps. VIII, IX, and X. 
b Geological Survey of California, Geology, vol. 1, 1865, pp. 135-138. 
c Twelfth Ann. Rept. California State Mining Bureau, 1894, pp. 498-506. 




12 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

The present writers are in agreement with these statements except 
as regards the exclusively Miocene age of The rocks, a large part of 
which are here considered as Eocene. On page 505 of Fairbanks’s 
article he speaks of “ shales and sandstones of undoubted Cretaceous 
age” between Gaviota Pass and Santa Ynez River, in the hills which 
in the present paper are considered as part of the Santa Ynez Range. 
In the very short time spent in this locality the present writers 
found no evidence of the presence of Cretaceous rocks. 

A number of asphalt deposits in northern Santa Barbara County 
are described on pages 30 to 33 of the twelfth annual report of the 
State mineralogist, cited above. The localities mentioned are on 
the Los Alamos grant, 41 miles north of Harris station; along the 
northern slope of the hills bordering the Santa Maria Valley, 10 miles 
southeast of Santa Maria; about 2 miles northeast of the Purisima 
Mission; along the southern slope of the hills between the Los Ala¬ 
mos and Santa Ynez valleys (Purisima Hills), especially on the San 
Carlos de Jonata grant; and in poorer and less known deposits at 
Gaviota Landing, at Point Arguello, near the mouth of Canada 
Honda, and at other points toward Lompoc Landing. Seepages 
out of the bituminous u slate” (shale) series are mentioned as occur¬ 
ring in the canyon of the Sisquoc, about in the center of the Sisquoc 
grant, along Labrea Creek, and near the west end of the Tinaquaic 
grant. 

By far the best observations recorded up to 1896 regarding the 
geology of this region were those of H* W. Fairbanks, published in 
his paper on the u Geology of Point Sal.” a He gives a detailed de¬ 
scription of the igneous and sedimentary formations occurring at 
the seaward end of the hills, termed in the present report the Cas- 
malia Hills. In speaking of the even summit line of the Point Sal Ridge 
he says: 

The regularity is due, in part at least, to the fact that the strata on the summit are 
nearly flat and composed of the resistant Miocene flints, while on the southern slope 
the bituminous shales are followed in descending order by a great thickness of gypsif¬ 
erous clays, in which broad valleys have been eroded. Lower down toward the 
ocean the clays are replaced by strata of volcanic ash, sandstone, and conglomerate, 
in which, because of their greater resistance, canyons have been eroded. The strata 
of volcanic ash form very striking features in the landscape on the lower slopes of the 
ridge; being interbedded with soft clays they weather out in cliffs and projecting 
ridges. 

In outlining the geology of the region of Point Sal Ridge, Fair¬ 
banks says: 

The region about the point itself has been the scene of many violent disturbances 
and repeated eruptions of basic magmas. A part of these consolidated as surface 
flows, while others have the characters of deep-seated rocks. 

The sedimentary strata comprise only the Pleistocene, Miocene, and Knoxville. 
* * * The Miocene is the most extensive formation represented. * * * It is 


a Bull. Dept. Geology Univ. California, vol. 2, No. 1, 1896, pp. 1-92. 



INTRODUCTION. 


13 


divisible into two distinct parts—the upper, the bituminous shales, and the lower, 
the gypsiferous clays. Below the clays are sandstone, shales, and conglomerates 
resting on the gabbro and serpentine. * * * The strata of volcanic ash appear in 
the lower Miocene beds. There are three distinct horizons, the lowest resting on the 
gabbro. 

The igneous rocks are treated in especial detail in this paper and 
a very good description is given of the bituminous shales. The con¬ 
clusions of the present writers are in agreement with the statements 
above quoted and the others contained in Fairbanks’s paper. 

In 1901 George H. Eldridge gave an admirable general outline 
of the topography and geology of the country surrounding the 
Santa Maria field in his treatise on “The asphalt and bituminous- 
rock deposits of the United States,” and discussed in detail its asphalt 
deposits. 0 He says: 

The geology of the region embraces an underlying series of folded Monterey shale 
of both the soft and more organic material and that which is hard and siliceous, but 
the former predominates. So far as observed by the writer this series of beds was 
not exposed at any point in its entirety. Overlying the Monterey unconformably, 
and especially developed in La Graciosa Hills, is the heavy and extensive deposit of 
Pliocene sands, grits, and conglomerate already referred to. The composition of the 
later deposit is chiefly quartzose. 

Eldridge “ observed a prevailing central fold somewhat to the north 
of the topographic axis of the ridge” south of Waldorf, in the Cas- 
malia Hills, this being no doubt the fold described in the present report 
as the Schumann anticline. He says further: 

The Pliocene * * * shows a less degree of folding than the underlying Mon¬ 

terey, yet the movement that produced the pre-Pliocene ridge has apparently been 
continued subsequent to the deposition of the materials of this age, for gentle dips 
of from 2° to 10° are to be observed in the later formation. 

In discussing the country east of Los Alamos, between the San 
Rafael Range and the Santa Ynez Valley, which he calls the Los 
Alamos region, Eldridge says: 

In structure the Los Alamos region presents a series of folds which are in general 
coincident with the topographic ridges and valleys. * * * It is worthy of note that 

the valleys of the region under consideration for the most part occupy the synclinal 
troughs. It is possible that some of them also occupy fault lines. * * * The gen¬ 
eral trend of the folds for the Los Alamos district, and indeed for a great stretch of coun¬ 
try beyond, is N. 70° to 80° W., the dips being north and south. Excepting in their 
trend, however, there is but little regularity in the disposition of the folds, and their 
axes, both longitudinal and transverse, vary greatly in length. In addition to the 
main and conspicuous folding that has been described, there are frequent crumples 
of minor importance. 

In another place Eldridge mentions a lens of limestone included 
in the serpentine in a high bluff just north of Alamo Pintado Creek, 
alomr the old beach line where the Fernando was deposited upon the 
Franciscan at the base of the San Rafael Mountains. This lime- 

a Twenty-second Ann. Rept. U. S. Geol. Survey, pt. 1, 1901, pp. 424-441. 

1784—Bull. 322—07-2 






14 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


stone was composed largely of Pliocene shells, as determined by 
Doctor Dali. Eldridge remarks: u In view of the supposed age of 
the serpentine, it is thought that the deposit was formed by the 
accumulation of sediment and shells in a crevice of the older rocks 
at the time they perhaps formed the sea bluffs.” 

The same writer published a brief summary of his knowledge con¬ 
cerning the Santa Maria district in 1903.® 

The San Luis folio, 6 by II. W. Fairbanks, issued in 1904, contains 
much that relates to the district in general, although it pertains 
directly only to the part containing the Arroyo Grande field. It 
is the most comprehensive report concerning the northwestern 
part of the Santa Maria district yet published. 

The present writers have published two papers concerning the 
geology and economic resources of the Santa Maria district. The 
first is entitled “ Diatomaceous deposits of northern Santa Barbara 
County, Cal.,” c and the second 11 Preliminary report on the Santa 
Maria oil district, Santa Barbara County, Cal.” d A third paper 
treating more in detail the burning of the shale is “ Metamorphism 
by combustion of the hydrocarbons in the oil-bearing shale of 
California/’ to be published in the Journal of Geology. 

EARLY HISTORY OF THE DISTRICT. 

The Santa Maria district was up to 1899 entirely unknown as an 
oil-producing territory. To Messrs. McKay and Mulholland, of Los 
Angeles, is due the credit for starting operations in the Santa Maria 
field proper. After a favorable report had been made by Mr. 
Mulholland on certain lands of the Careaga ranch, the Western Union 
Oil Company was organized, drilled three prospect holes, and was 
finally rewarded in August, 1901, by striking paying quantities of 
oil in the third well. In 1902 the Pinal Oil Company, of Santa Maria, 
began operations on the north side of Graciosa Ridge, and meeting 
with marked success was followed by the many other companies 
that have since undertaken operations in this field. 

Successful wells were drilled in the Lompoc field in 1904, and since 
that time the further development of this part of the district has 
been assured. A later field to attract attention is that adjacent 
to the town of Arroyo Grande, where development is well under way, 
being stimulated by the completion of the successful Tiber well 
No. 1 late in 1905. Prospecting is now (January, 1907) going 
forward in the Huasna field east of the Arroyo Grande field, and the 
operators there confidently expect to develop productive wells. 

a Contributions to economic geology, 1902: Bull. U. S. Geol. Survey No. 213,1903, p. 313. 
b Geologic Atlas U. S., folio 101, U. S. Geol. Survey. 1904. 
c Bull. U. S. Geol Survey No. 315, 1907, pp. 438-447. 
dBull.U. S. Geol. Survey No. 317, 1907, pp. 1-09, 2 pis., l fig. 



SANTA MARIA OIL DISTRICT, CALIFORNIA. 


15 


GEOGRAPHY AIN'T) TOPOGRAPHY. 

LOCATION. 

The region discussed in this paper is situated on the California coast 
in Santa Barbara County, between 120° and 120° 40' west longitude 
and 34° 30' and 35° north latitude. In areal extent it is about 1,300 
square miles and it practically covers the Lompoc and Guadalupe 
quadrangles as topographically mapped by the United States Geo¬ 
logical Survey. It includes portions of the San Rafael and Santa 
\ nez divisions of the Coast Ranges and the basin region lying between 
them, which is occupied by the Santa Maria, Los Alamos, and Santa 
Ynez valleys and the intervening hill ranges. It is bordered on the 
north by the San Luis Obispo County line, on the west and south by 
the Pacific Ocean, and on the east by the Santa Ynez quadrangle, 
which covers the high, wild mountains north of Santa Barbara. On 
its west coast are Point Sal and Point Arguello, and the south coast 
includes Point Conception and part of the long, straight shore line 
that runs due east from that point toward Santa Barbara. These are 
among the most prominent coastal features of California. 

The region is thoroughly intersected by roads, except in some of 
the uninhabited portions. The Southern Pacific Railroad coast line, 
part of the transcontinental system, extends close to the ocean entirely 
around two, sides of the area, and the Pacific Coast Railroad, a local 
line from Port Harford and San Luis Obispo, runs into the region as 
far as Los Olivos via Santa Maria. A rough estimate would place 
the number of inhabitants of this region between 5,000 and 10,000. 

The Arroyo Grande and Huasna oil fields, in the San Luis quad¬ 
rangle, San Luis Obispo County, are also briefly mentioned, although 
not a part of the region whose general features are described in this 
report. 

DEFINITIONS OF PLACE NAMES. 

The following list defines certain place names as used on the map 
and in this report. The two main mountain ranges have heretofore 
been indefinitely designated The other names are newly applied. 

The only land comprised within the Guadalupe quadrangle is the 
narrow strip of coast west of longitude 120° 30' W. The Lompoc 
quadrangle covers the rest of the area shown on the map east of that 
line. 

The San Rafael Mountains include the whole group between Santa 
Ynez and Cuvama rivers. 

The Santa Ynez Mountains include the whole range east of Point 
Arguello between Santa Ynez River and the ocean. 


16 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

The Casmalia Hills include the group extending from the coast at 
Point Sal to Graciosa and Harris canyons and San Antonio Valley. 

The Solomon Hills lie between the Santa Maria Valley, Foxen 
Canyon, and the Los Alamos Valley, and between Divide and La 
Zac a Creek. 

The Purisima Hills lie between Lompoc, the Santa Rita Valley, and 
the Santa Ynez Valley on the south and the Los Alamos Valley on 
the north, and between Burton Mesa on the west and Alamo Pintado 
Creek on the east. 

The Santa Rita Hills lie between the Santa Ynez and Santa Rita 
valleys, extending from a point east of Lompoc nearly to the east 
edge of the Santa Rosa grant. 

The name San Antonio terrace is applied to the wide terraced region 
between Casmalia and the west end of the Los Alamos Valley. 

The Lompoc terrace is the plateau-like region of hills extending 
from the coast a distance'of about 5 miles east from Honda and the 
same distance southeast from Surf. 

In 1896 Id. W. Fairbanks used the names “Point Sal Ridge" for 
the axis of the hills between Mount Lospe and Point Sal, and “Lions 
Head” for a high, rugged mass of serpentine on the coast south of 
Point Sal. These features are so named here. 

RELIEF. 

GENERAL STATEMENT. 

The general character of the region covered by the Lompoc and 
Guadalupe quadrangles is that of a triangular hilly basin opening 
out toward the coast between two divergent ranges of mountains—the 
San Rafael Range in the northeast portion of the area and the Santa 
Ynez Range bordering it on the south. At the east edge of the area 
mapped these ranges are divided only by the valley of Santa Ynez 
River and the foothills north of it. Farther west the distance between 
them grows to 30 miles or more. The region situated in this angle is 
primarily a basin, owing its character and the details of its structure 
to its position between these ranges. This basin region, its struc¬ 
ture, and its oil deposits form the principal subjects of discussion in 
the present paper. 

Two lines of hills and three valleys occupy this trough between the 
two main ranges, radiating like the intermediate ribs of a fan between 
the lines that bound them. The more northerly of the two lines of 
hills is that of the Solomon and Casmalia hills, which are separated 
from the San Rafael Mountains by the wide valley of Santa Maria 
River. The more southerly is the range of the Purisima Hills, which 
is separated from the Santa Ynez Mountains by Santa Ynez River. 
These two lines of hills are themselves divided by Los Alamos Valley. 


GEOGRAPHY AND TOPOGRAPHY. 


17 


They are topographically and structurally young ranges, except the 
Oasmalia Hills, at the extremity of the northern line, which have the 
character of a separate and old range. 

SAN RAFAEL MOUNTAINS. 

The most prominent topographic feature is the great mass of the 
San Rafael Mountains on the northeast and east, 25 to 30 miles 
back from the ocean. The structural trend of the range is N. 50° W., 
approximately parallel with the general course of the lines of struc¬ 
ture in California, although on the whole more westerly. The range 
runs obliquely to the north-south coast line west of it, but farther 
north, where the Santa Lucia Range, its northward continuation, 
approaches the ocean the coast curves to the northwest under the 
control of the mountains. 

Although the portion of the San Rafael Range included within 
the area shown on PI. I (pocket) composes a high, rugged maze of 
ridges reaching elevations that range between 2,000 and 4,300 feet, 
this portion is in the larger aspect, but subsidary to the main moun¬ 
tain group farther east, in which altitudes approaching 9,000 feet 
are attained. The ridges are divided by steep canyons, most of which 
cut transversely across the formations regardless of the folding and 
structural lines. Rounded soil-covered slopes form a considerable 
portion of the part of this range included in the Lompoc quad¬ 
rangle, but rough, rocky slopes are likewise abundant. The range 
is traversed centrally by the well-graded canyon of Sisquoc River, 
which divides it into two mountain groups. On the south and north 
the range is bounded by wider graded valleys—those of Santa Ynez 
and Cuyama rivers. The Santa Ynez divides two distinct ranges. 
The Cuyama forms a more arbitrary division in the Coast Ranges. 
Near its mouth, at the point where it reaches the area included in 
the accompanying map, it veers to the south and cuts a narrow gorge 
across the San Rafael Mountains without regard to the structure. 
The range may be regarded as continuous across this portion of the 
river. 

Within the triangular area mapped the high ridges and mountains 
around Zaca Lake, Bone Mountain, Tepusquet Peak, and Los Coches 
Mountain are boldly defined, with steep side slopes descending into 
narrow canyons, and as a rule rounded summits. The broad ridge 
oridnatinsr north of Los Coches Mountain and extending southeast- 
ward to North Fork of Labrea Creek, where its character is tem¬ 
porarily lost until it appears again in Manzanita Mountain, is a 
striking feature with its long southwestern and abrupt northeastern 
slopes. The seaward flanks of the range terminate rather abruptly 
in the terraces bordering the Santa Maria Valley. 


18 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


SANTA YNEZ MOUNTAINS. 

The Santa Ynez Mountains form a long, narrow range bordering 
the Santa Barbara Channel and bounded on the north by the westward 
flowing Santa Ynez River. The trend of the range is east and west 
and has determined the unusual direction taken by the coast south 
of it. The range is about 9 miles in average width and contains two 
lengthwise zones. The southern zone comprises a ridge with remark¬ 
ably even sky line, which rises directly from the sea. This ridge 
increases in height toward the east from an elevation of 1,000 feet 
at Point Conception to 3,800 feet east of Refugio Pass and more 
beyond the boundary of the area mapped. At Point Conception 
the coast bends abruptly to the northwest around the end of this 
ridge, but north of Jalama Creek a similar ridge, that of the mountain 
El Tranquillon, follows the coast as far as Point Arguello, where the 
shore bends again abruptly and assumes a northward course. The 
second zone lies between these two coast ridges and Santa Ynez 
River. It has more the nature of a foothill region, forming a partly 
individual range of hills and ridges separated from the coastal ridge 
by longitudinal valleys. The average slope from the summit of the 
range down to the sea is at an angle of 20° to 30°. In places the 
angle is less, but on some individual slopes it is greater. The width 
of the range on the north of the summit ridge is greater and the slope 
more gentle and more broken than on the southern abrupt slope to 
the sea. Viewed from the ocean on the south the range has the 
appearance of a steep, even-topped breastwork; from the north it 
appears as a belt of discontinuous hills and ridges grouped in front 
of and almost hiding the long culminating ridge. The Santa Ynez 
Range forms the most prominent elbow on the California coast. 

The topography of this range reflects the structure more than 
does that of the San Rafael Mountains, and deformation within it 
does not appear to have gone so far. 

In the high mountainous region east of the area mapped, north 
of Santa Barbara and south of the south end of the great central 
valley of California, centering at Mount Pinos, lies the point of con¬ 
vergence of all the ranges of mountains in this part of California- 
the Santa Ynez Range coming in from the west; the San Rafael 
Range from the northwest; the Santa Lucia and San Jose ranges 
from the country north of Cuyama River; the Mount Diablo Range, 
or ^easternmost member of the Coast Ranges, from still farther north 
of west; the Tehachapi Range, running south westward from the 
south end of the Sierra Nevada; and the San Gabriel Range, which 
comes from the southeast as the continuation of the Coast Ranges 

O 

in southern California. Here the northwest-southeast lines of 
structure, dominant throughout the major part of the State, are met 


GEOGRAPHY AND TOPOGRAPHY. 


10 


and opposed by the east-west structure of the Santa Ynez Range, 
and the result is this convergence of ranges with the consequent 
formation of a high, structurally complex region. The Lompoc 
quadrangle is on the western outskirts of this region, and the lines 
of relief corresponding to the two lines of structure are here begin¬ 
ning to diverge and show their individuality in the two bounding 
ranges. 

SANTA MARIA VALLEY. 

Santa Maria River, which takes its rise in two profound valleys 
within the San Rafael Range, flows along the foot of this range at 
the north edge of the Santa Maria Valley. This valley is a wide 
flood plain with an even cultivated floor, surrounded by low terraces 
that fringe the base of the mountains on the northeast and rise into 
the Solomon Hills on the south. It opens out to the sea and forms 
the southern part of the low region lying between Pismo Beach in 
San Luis Obispo County and the Casmalia Hills. 

C ASM ALIA HILLS. 

The most prominent feature of the landscape south of the Santa 
Maria Valley is a long ridge with a level sky line running northwest¬ 
ward out to the ocean at Point Sal. This is the high ridge of the Cas¬ 
malia Hills, which rises abruptly from the Santa Maria Valley. Its 
highest point is Mount Lospe, 1,624 feet above the sea. The slope 
up to this ridge from the valley on the northeast is steep, but on the 
north the rise is more gradual over wide slopes of dune sand. On 
the southeast the ridge declines as it approaches Schumann Pass^ 
the low divide over which the railroad crosses from the Santa Maria 
Valley to Schumann Canyon; on the south it forks into successive 
ridges which slope gradually into terraced hilltops bordering Schu¬ 
mann Canyon; on the west it drops off abruptly into steep, rocky 
declivities that fringe the sea in the neighborhood of Point Sal. The 
ridges continue southeastward opposite Schumann Pass as far as 
Graciosa Canyon, where they sink under more recent sand formations 
and lose their character. South of Schumann Canyon the terraced 
slope continues in the San Antonio terrace as a wide plateau locally 
intersected by sharply defined U-sliaped canyons. The Casmalia 
Hills, particularly that portion north of Schumann Canyon, have a 
distinct individuality among the topographic features of the basin 
region, and may be regarded as a separate although small range 
allied in age and character with the bounding ranges. It is conform¬ 
able in trend with the San Rafael Mountains and forms a prominent 
headland jutting out to sea. 

Most of the ridges in these hills follow the strike of the beds. 
Their summits are characteristically of gentle incline; the side slopes 


20 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


range from gentle to fairly steep, being in many places determined 
by the dip. PI. IX, A (p. 80) shows excellent examples of the strike 
ridges, dip slopes, and even sky lines of these hills. The ridges di¬ 
verging from Mount Lospe are given prominence by the hard flint of 
which they are formed, and the sharp outlines of the slopes along the 
coast southward from Point Sal are caused by the resistant igneous 
rocks there exposed. 

South of the Casmalia Hills the sea has cut into soft formations 
and along structural lines, so as to leave the Point Sal Ridge jutting 
out as a promontory. The same is true on a smaller scale south of 
Purisima Point, the seaward extension of Burton Mesa, and south 
of the west end of the Santa Ynez Range. The coast north of each of 
these headlands runs northward, with only a gentle curve away from 
the point, until the indentation south of the next range is reached. 
The east-west coast lines follow structural features; the north-south 
lines truncate them. Faults are not concerned in any of the north- 
south features along this part of the coast. 

North of the Casmalia Hills the coast forms a straight north-south 
line bordering the lowland that opens out at the mouth of the Santa 
Maria Valley as far as the deep indentation at the base of the San 
Luis Range, which exhibits the best example of this type of coastal 
structure. The latter range lies in the San Luis quadrangle and has 
been described in the folio covering that region. 0 

SOLOMON HILLS. 

Although the Casmalia Hills drop into insignificance in the vicinity 
of Graciosa and Harris canyons, their general line of topographic 
relief continues with a more easterly course toward the San Rafael 
Mountains, the whole being in fact a spur of this range. The Solo¬ 
mon Hills are a group of low, rolling hills covering a wide area between 
the Santa Maria and Los Alamos valleys. From a distance the area 
looks like an undulating plateau sloping away on all sides except the 
east to wide, slightly inclined or flat valleys. 

The features of the topography of the Solomon Hills are shown 
in PI. XI (p. 98). From a point near at hand the individual hills 
and valleys of irregular round and square forms assume bold outlines. 
The angular slope of hills capped with low-dipping beds of sand and 
having steep, squarish flanks is very characteristic of the region. 
Many ridges have fairly flat summits, which slope gently, with a long, 
even sky line, and are due to surface cappings of sand hardened by iron 
oxide. Such a capping has in places the appearance of a resistant 
bed forming the ridge top and determining the slope by its low dip. 

Mount Solomon has an elevation of 1,338 feet and other peaks rise 


a Geologic Atlas U. S., folio 101, U. S. Geol. Survey, 1904. 





GEOGRAPHY AND TOPOGRAPHY. 


21 


as high as 1,600 feet. A common height for summits in these hills 
is 1,200 feet, 

A\ ide, shallow, filled valleys between the rolling summits are char¬ 
acteristic of the Solomon Hills, the soft valley filling being as a rule 
sharply cut along a meandering course by a miniature stream gorge 
that has been rapidly eroded. Many of these recent channels are 
deeper than they are wide. In the vicinity of La Zaca Creek on the 
east the Solomon Hills merge with these foothills, and the general 
topographic features are continued in them. The Solomon Hills 
owe their low outlines largely to their structural development rather 
than to their topographic maturity. It has been an area of building 
up as well as of wearing away, and the original topography, which 
reflected characteristically the folds of the sedimentary formations, 
has been obscured by further deposition and by the filling of valleys, 
in addition to alteration by erosion. 

LOS ALAMOS VALLEY. 

The incline of the Solomon Hills on the south is gradual down to 
the Los Alamos Valley. This valley extends from the region where 
the Solomon and Purisima hills coalesce in the foothills of the San 
Rafael Range a distance of about 27 miles to the coast, in a direction 
about N. 75° W. This, it will be noted, is much more westerly 
than the trend of the Santa Maria Valley. The Los Alamos Valley 
separates the two basin ranges—the Solomon and Purisima hills— 
and is a drainage feature of them alone. The average altitude at the 
summit of its watershed is from 1,000 to 1,300 feet; and the highest 
elevation that the watershed reaches anywhere is less than 2,000 feet. 
All the water from the higher surrounding regions that drains into 
the Santa Maria basin region escapes either into the Santa Maria 
Valley on the north or the Santa Ynez Valley on the south. 

PURISIMA IIILLS. 

The second of the two hill ranges is that of the Purisima Hills, which 
forms a definitely outlined structural and topographic unit spring¬ 
ing from the plateau region about Santa Ynez and the foothills of the 
San Rafael Range in the vertex of the triangular basin. It rises at 
that point in the shape of a number of strike ridges which run north¬ 
westward and then curve around to the west, coming together. For 
most of the distance to the ocean beyond this junction the range con¬ 
sists of a single ridge running parallel to the Los Alamos Valley. On 
the north it sends out lateral ridges that drop off rather abruptly into 
the Los Alamos Valley. These ridges are separated by fairly sharp 
V-shaped valleys, although some of the valleys have sides of more 
gentle slope and filled bottoms. A striking topographic feature is a 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


22 


longitudinal trough running for miles parallel with this range and the 
Los Alamos Valley and cutting across the ends of the above-mentioned 
ridges at right Angles to them, at a distance of one-half to 1 mile from 
the valley. It notches all the ridges and leaves an individual row of 
knobs 100 to 200 feet in relief bordering the valley. This depression 
is not a continuous drainage feature, but is stratigraphically of impor¬ 
tance as approximately marking the contact between the Monterey 
shale and the loose Fernando sand. On the south side of the summit 
of the Purisima Hills the lateral ridges extend a long way with a uni¬ 
form gentle slope, like remnants of an eroded inclined plateau. At 
their base, some miles from the summit, and usually from 500 to 1,000 
feet below, these southern slopes merge into an undulating hilly 
plateau 'that has the appearance of being buried under soft recent 
sand. The range is broadest at the east end, where it consists of a 
number of parallel ridges. The point of convergence of some of these 
is Redrock Mountain, which is 1,968 feet high and the highest summit 
in these hills. Thence westward the hilly zone narrows into a single 
central ridge and its offshoots, and gradually pinches out, finally giv¬ 
ing place on the south and west to a broad terrace in which its hilly 
character is lost. The summit of the main ridge of the Purisima 
Hills west of Redrock Mountain gradually declines in height and for 
most of the way it is remarkably even, the elevation varying between 
1,200 and 1,000 feet. At the elevation of 1,000 feet it grades into 
the smooth terrace called Burton Mesa. 

BURTON MESA. 

Burton Mesa is a marine terrace covering more than 50 square miles, 
which slopes, with an average gradient of 2|per cent, away from the 
west end of the Purisima Hills, reaching the sea within 7\ miles. It 
is composed of Monterey shale, in the main rather gently folded, 
which has been planed off and covered with a thickness of about 25 
feet of horizontal gravel and loose sand. From the elevation of 1,000 
feet, where the continuous sheet of sand overlaps on the end of the Puri¬ 
sima ridge, down to the 600-foot level the distance in a west-south¬ 
west direction is three-fourths of a mile and the slope 10 per cent. 
Within the next three-fourths of a mile a drop of 100 feet occurs, the 
slope being per cent. Beyond lies the main level stretch of the 
plateau for a distance of 5 miles, with no greater slope than three- 
fourths of 1 per cent until the elevation of 300 feet is reached, in the 
southwest corner of the mesa, where there is an abrupt change to a 
10 per cent slope, the distance down to elevation 100 feet being only 
one-third of a mile. Below the 100-foot level there is a bench with 
a 3 per cent grade as far as the edge of the cliff which faces the sea, 
and which is in most places about 25 feet above the water. North 


Geography and topography. 


28 


of Canada Tortuga the steeper portion above the coastal bench is only 
100 feet high, and in the northwest corner of the mesa the main 
terrace and the coastal bench grade into each other and become 
practically one. 

SANTA YNEZ VALLEY AND SANTA RITA HILLS. 

Santa Y nez Itiver is the second of the two main drainage lines of 
the area, Los Alamos Creek, the next in size, being much subordinate 
to these two. The Santa Ynez rises in the high region north of Santa 
Barbara and flows westward between the Santa Ynez and San Rafael 
ranges. From the east edge of the Lompoc quadrangle, where these 
two ranges diverge, it flows slightly to the north of west, at the foot 
of the Santa Ynez Mountains. Its course is even more westerly than 
that of the Los Alamos Valley until it approaches the ocean, where 
the. nose of the Santa Ynez Range, as in the two ranges farther north, 
shows a tendency to change its orientation into greater conformity 
with the northwesterly course of the San Rafael Range. 

This stream has a low gradient of only one-fourth of 1 per cent. Its 
valley has a steep side on the south formed by the hills of the Santa 
Ynez Range, but it is widened on the north by the easy slopes of ter¬ 
races and santl hills, except at the Santa Rita Hills, which rise midway 
in the river’s course. 

r' 

The Santa Rita Hills form a small separate range .reaching a height 
of 1,300 feet and resembling in miniature the Purisima Hills. The 
range starts from the valley in several strike ridges running north¬ 
west, which join in the highest part of the range and then continue 
due west as a single ridge. The river follows a tortuous course be¬ 
tween this and the Santa Ynez Range and has cut cliffs in many places. 
On the north the Santa Rita Hills are divided from the Purisima 
Hills by the Santa Rita Valley, a low basin similar to some portions 
of the Santa Ynez Valley. 

The level floor cf the river valley, including the stream bed and the 
somewhat higher terrace-like flats on either side, ranges in width from 
a few hundred feet to about a mile until within 10 miles of the ocean, 
where it opens out into the Lompoc Valley, an alluvial flat several 
miles wide. 

TERRACED COAST. 

Pleistocene terraces border the coast for the greater part of the 
distance around the Guadalupe and Lompoc quadrangles. The 
great Burton Mesa terrace has already been mentioned. Beyond the 
valleys to the north and south of this mesa similar terraced areas 
extend widely and in places to a considerable distance inland, but no¬ 
where else with so gentle a slope as is exhibited on the Burton Mesa. 


24 


SANTA MARTA OTL DISTRICT, CALIFORNIA. 


Where steep hills descend toward the coast there is almost without 
exception a coastal terrace starting at the top of the sea cliff, which, 
as a rule, ranges in height from a few feet to more than 50 feet above 
the water. Most of these terraces extend up to an elevation greater 
than 200 feet. Some of them have left traces at a height of 300 feet 
or more, and others continue perfect to this altitude or even higher. 

GENERAL TOPOGRAPHIC FEATURES. 

The point of especial interest in the topography of the central region 
between the two bounding ranges is its characteristic reflection of the 
structure of the formations, whereas in the mountains, as has been 
noted, the topographic development has been less in accordance with 
the lines of structure. An anticline in the central region is apt to be 
coincident with a ridge, as, for example, in the long ridge of the 
Purisima Hills, which lies close to the axis of a broad anticline. 
Moreover, some of the larger valleys mark the synclinal axes of the 
broad lines of structure—a statement illustrated by the Santa Ynez 
Valley in parts and by its structural, although not actual, continua¬ 
tion in the Santa Rita Valley. It is also exemplified bv the upper por¬ 
tion of the Los Alamos Valley and by Harris Canyon. These topo¬ 
graphic features may be accounted for by the facts that the main 
movements in these hill ranges have been gentle as compared with 
those in the older mountain masses, that the disturbances giving 
them form have been comparatively recent, and that deformation 
has not gone so very far. Wherever there are low areas of rolling 
hills it is almost sure to be found that a syncline or plunging fold has 
given rise to structural depressions in which deposits of soft sand pro¬ 
ducing low topographic forms have been laid down. 

The character of the different formations shows its influence on the 
topography. The areas of serpentine with associated Franciscan rocks 
have irregular broken surfaces with many outcrops and usually an old, 
well-worn appearance. The dominantly sandstone and shale terranes 
described under the headings “pre-Monterey rocks” and “Vaqueros, 
Sespe, and Tejon formations, undifferentiated,” do not give rise to a 
very distinctive topography. They form a succession of ridges and 
V-shaped canyons of moderate relief and comparative regularity. In 
many places the truncated edges of the tilted strata form steep, rough 
strike slopes. The Monterey shale produces the forms of highest relief 
in this region, as well as forms of low relief, according to the amount 
of folding that has taken place in it and to its hardness. The 
brittle shale closely folded gives rise to sharp ridges, many of them 
serrate, with steep, rocky flanks. Ridges of highly tilted shale are 
shown in PI. VI, B (p. 46). The lower folds produce hills of gentle 
incline and long unbroken ridges, in places parallel with the strike 


GEOGRAPHY AND TOPOGRAPHY. 


25 


and having a dip slope, as shown in PI. IX, A (p. 80). Character¬ 
istic of the soft shale are hills having the form of mounds with sym¬ 
metrical rounded contours and with few prominent outcrops except 
pavements of shale forming- the surface. The soft Fernando sands 
form small hills that look like irregular sand piles, and long slopes 
with shallow erosion features. Some of these slopes reflect the 
dip of the strata on the flanks of low folds and are structurally 
inclined plateaus in a typical state of youthful dissection. The val¬ 
leys are, in many places, filled with sand that has shifted down from 
the hills faster than it could be carried away by agencies of transpor¬ 
tation. Great cliffs of soft sand are common as the result of the rapid 
undermining and removal of portions of hills. Thus walled cirques 
are formed. Harder materials in the Fernando cause squarish forms, 
such as that of Mount Solomon. The terraces of the Quaternary 
give a strong individuality to the topography of this region. They 
are widely in evidence along the coast, in valleys, at all levels up to 
1,200 or 1,400 feet on slopes, on hilltops, and along horizon lines. 

DRAINAGE AND RAINFALL. 

The three principal streams have received mention under the pre¬ 
vious headings. A small amount of water runs in them all the year 
round, but the quantity is only rarely sufficient in either of the two 
main streams to warrant their being called rivers. This name is 
applied to them on the ground of the importance of their drainage 
areas. Almost all the drainage of the two quadrangles flows into 
these three streams. In the main they run parallel to the strike of 
the formations. In addition to those already mentioned, others that 
run independently into the sea are Casmalia Creek, in Schumann Can¬ 
yon, which first cuts obliquely across the end of the Casmalia Hills 
and then assumes a longitudinal course; Canada Honda Creek and 
Jalama Creek, the two last having deeply cut courses parallel with the 
structural lines at the west end of the Santa Ynez Mountains. The 
steep seaward slope of these mountains is cut into by a great number 
of short, steep, transverse gorges. 

The portion of the San Rafael Range lying within the area covered 
by the map is drained principally by Sisquoc and Cuyama rivers, 
which flow along well-graded courses, and by the minor streams, 
Labrea and Tepusquet creeks. With the exception of the Cuyama, 
these watercourses and the majority of the others in the mountains 
have cut transverse canyons across the formations regardless of the 
folding and the structural lines. In this respect they differ from the 
streams farther south. 

On the whole, it is rather a dry region. An average of only 12 or 15 
inches of rain falls annually, during the winter rainy season. During 


26 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

the long dry season almost complete evaporation of surface moisture 
takes place, and there is little erosion through the aid of water. 
Throughout the latter part of the Quaternary period the rate of ero¬ 
sion has probably been slow. 

CLIMATE AND VEGETATION. 

The climate of this area is that of the coastal region of California. 
It is equable the whole year round, excessive heat or cold being 
very rare. The days are mild, the nights chilly. The region is sub¬ 
ject to the inroads of heavy fogs and driving winds from the open 
ocean, but this is true to a lesser degree in the eastern angle of the 
basin, where there are protecting hills on all sides. The winds 
blow very strongly from the west and northwest up the radiating 
valleys that open to the coast. The region is subject to earth¬ 
quakes, some of which would seem to be of local origin. 

The vegetation in the northern part of Santa Barbara County is 
open, as in the neighboring portions of California. There are almost 
no dense groves of trees, most of the hills being sparsely clothed 
with a scattering growth of small trees, usually live and white oaks, 
and bushes, or else entirely bare, except for sagebrush and grass. 
The wide terraces and hills of soft sand are commonlv overgrown 
with so-called tarweed and are otherwise almost bare. In the val¬ 
leys near the coast grow many willows; in the more protected val¬ 
leys farther inland thrive large sycamores, cottonwoods, and live 
and white oaks. The steep slopes of the San Rafael Range are 
sparsely set with small oaks, pines, and yuccas, and, like those of 
the Santa Ynez Range, are covered in parts by dense thickets of 
undergrowth. 

The vegetation of the hill ranges of the basin region is typically 
illustrated by PI. IX (p. 80) and of the San Rafael Mountain region 
by PI. VI (p. 46). 

GEOLOGY. 

SEDIMENTARY FORMATIONS. 

GENERAL STATEMENT. 

The formations involved in the geology of this district (see PI. II) 
include the Franciscan (Jurassic?); Knoxville (lower Cretaceous); 
pre-Monterey rocks (which may include both Cretaceous and older 
Tertiary); Tejon, Sespe, and Vaqueros, undifferentiated (Eocene- 
Miocene); Monterey (middle Miocene); Fernando (Miocene-Pliocene- 
Pleistocene); and Quaternary. The maximum known thickness of the 
Tertiary and early Quaternary formations combined is 13,200 feet. 
The following table shows the correlation of these formations with the 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. II 


Alluvium (1' —100'+)_ 

Sand dunes (10' —300' + ) . 
Terrace deposits (30' + )... 
Unconformity. 


Q -,p • Q...Q.V 

W.c&Wf&'+i ! 

•* ". « *• - ••• Q. 


Fernando formation (3,000'+). ' 


- r-o-v:-Q-: 


Unconformi t y. 




Monterey shale (5,400'+).( =-=== 


W estern 
Union. 


Zone A. 


:-.6v O O. -p ' ® 

■.«» • PfQ: O.VoV-ZP.p. ■ 


Vaqueros, Sespe. and Tejon , 
formations, undifferentiated ‘ 
(5,000' + ). 


Sand. clay, gravel, and earth. 

Marine sand, loosely aggregated and slightly ho-izontally bedded. 

Sand, gravel, and clay, often hardened by iron oxide. Seepage from Monterey often causes asphalt deposits 


Slightly consolidated gravel, sand, and clay. 
Brackish-water limestone and alkaline sand. 


Fine, soft, yellow sand near bottom, grading upward into coarser white and gray sand and gravelly conglomerate. 


Fine, white, diatomaceous shale and fine, white and greenish sand. Local breccia and asphalt deposits (shown 
in black). 


Soft, white, thin-bedded, diatomaceous earth or shale, with intercalated beds and lenses of concretionary lime 
and hard, brittle, siliceous shale due to metamorphism. Occasional fine sand beds. Shale locally bituminous ; 
gypsiferous near top. 


Thinly stratified and much-contorted hard, brittle, and siliceous shale, often flinty, with some soft, unmetamor¬ 
phosed diatomaceous shale and frequent beds of limestone and flint. Tuff and volcanic ash occur locally; 
Shale bituminous. Four principal petroleum zones shown in black and auxiliary zones indicated. 


Alternating beds of dark clay shale, sandy shale, and sandstone; frequent massive limestones near top. Thick 
beds of line and very coarse conglomerate in upper portion. Shale and sandstone thin-bedded; sandstone 
becoming more massive toward top. 


The relation of the formations above to those below is not known. 


The rocks mapped as pre-Monterey may till this gap and lap over onto the formations above and beh > w. 


r 


Knoxville formation (3,000'=t). 
Not extensively recognized, j 
Thickness and character as - 
described by Fairbanks in ad¬ 
jacent San Luis quadrangle. 


I 

Unconformity. f 


Franciscan formatio n (1.000'+=). .j 


COLUMNAR SECTION OF THE SEDIMENTARY ROCKS OF THE LOMPOC AND GUADALUPE QUADRANGLES. 




r-o•,-.o;•.o.-T o. . - ,<P •: o.. 




Dark, thin-bedded clay shale, with thin irregular layers of conglomerate at bottom and near middle. 


Largely intrusive serpentine, associated with much-contorted banded jasper, dark, greenish hard sandstone and 
shale, and with some glaucophane schist. 







































































































































































































' 





































































































GEOLOGY. 


27 


standard California section and with that of Santa Clara Valley, Ven¬ 
tura County: 


7 entative correlation of formations of Santa Maria district with the standard California 
Coast Range section and with that of the Santa Clara Valley. 


Era. 

Sys¬ 

tem. 

Period. 

Standard Coast Range 
section. 


u 

s 

Recent. 

Alluvium. 


£ 

CS 

& 

Pleistocene. 

San Pedro. 



Pliocene. 

—— Unconformity—— 
Merced. 




Purisima. 

o 

O 



San Pablo. 

N 

o 

c 

s 

o 

Sh 

.2 

u 

Miocene. 

Monterey. 


a> 

H 


Vaqueros. 



Oligocene. 

San Lorenzo. 

— Unconformity? — 

Tejon. 



Eocene. 



Martinez. 

— Unconformity? — 
Chico. 

-Unconformity- 

Horsetown. 

-Unconformity- 

Knoxville. 

d 

o 

N 

o 

Cretaceous. 


CO 

o> 

Jurassic (?). 


-u nconiormiLy — 

Franciscan. 

-Unconformity- 

Granite, schist, etc. 


Santa Maria district 
section. 


Alluvium. 


Terrace deposits and 1 
dune sand. 

-Unconformity- 


Fernando. 


Unconformity- 


Monterey. 


Vaqueros, Sespe, and 
Tejon, undifferenti¬ 
ated (including some 
Monterey in " Santa 
Ynez Range). 


(?) 


Knoxville. 


Franciscan. 


Santa Clara Valley 
section. 


Alluvium. 


Sand and gravel. 

— Unconformity — 


Fernando. 


-Unconformity 


_c 

XJ' 

O 


Shale. 

Upper sandstone. 
Shale. 

Lower sandstone. 


Vaqueros. 


g. (Upper, 
ml Red beds. 
oq [Lower. 


Topatopa. 


(?) 


-Unconformity —— 

Granite, gneiss, etc. 


FRANCISCAN FORMATION (JURASSIC?). 

The oldest rocks within the Santa Maria district belong to the Fran¬ 
ciscan formation, which is probably of Jurassic age. H. W. Fair¬ 
banks described the same formation under the name San Luis in the 
San Luis folio. The Franciscan is a very important basement for¬ 
mation in the Coast Ranges farther north. The small areas of these 
rocks occurring here consist of remnants of beds of sandstone, shale, 
glaucophane schist, and jasper associated with serpentine that has 
probably been intrusive in them. The sandstone is usually of a dark- 
green color, fairly fine grained, and considerably indurated. The 
jasper is banded by thin contorted beds, These sediments are so 


















































28 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

disturbed that little clew as to their structure can be obtained, and 
so local in extent that no attempt has been made in mapping to 
differentiate them from the accompanying serpentine. 

KNOXVILLE FORMATION (LOWER CRETACEOUS). 

Several small areas of sedimentary rock occur which can be defi¬ 
nitely assigned on fossil evidence to the Knoxville, or lower Cretaceous. 
The two most important are north of Mount Lospe. in the Casmalia 
Hills. The rock is chiefly dark-colored, unaltered argillaceous shale, 
such as is characteristic of the Knoxville throughout its wide area 
of distribution in the California Coast Ranges. Sandstone and con¬ 
glomerate occur in lesser amounts. Brownish-yellow sandstone, 
similar to that common in the Knoxville in the Coast Ranges several 
hundred miles farther north, occurs on the border of an irregular 
area of diabase on Tepusquet Creek, in the San Rafael Mountains, 
and contains the characteristic Knoxville fossil Aucella piochii Gabb 
(PI. XIII, figs. 1, 2, 3a, 3b, p. 128). The rock is present only in very 
small patches, and seems to have been brought up from below by the 
diabase intrusion. The Knoxville was recognized in one other place 
in the San Rafael Mountains a few miles north of Zaca Lake, at the 
base of the series mapped as pre-Monterey, where also it contains 
Aucella piochii. It is very likely that a portion of the areas mapped 
as pre-Monterey belongs to the lower Cretaceous, but it is not prob¬ 
able that the whole does. 

PRE-MONTEREY ROCKS. 

Two large areas of sedimentary rocks whose age has not been 
determined otherwise than that they are older than the Monterey 
occur in the San Rafael Mountains. They are mapped as pre- 
Monterey rocks. It is probable that strata of Knoxville (lower 
Cretaceous) age occur at the base of the series in those areas and 
that the higher portions represent either the upper Cretaceous or 
the Eocene, or both. Detailed work was left until another time. 

The larger of these two areas occupies the northeast corner of the 
region shown on the map, and is about 60 square miles in extent. 
The other lies on the northeastern slope of the high ridge north of 
Zaca Lake. In these areas are exposed a great series of thin-bedded, 
dark-colored, locally greenish shale alternating with more massively 
bedded sandstone, which is in places of a very granitic nature. Con¬ 
glomerate, much of it plainly evidencing its origin from granite, 
occurs in minor horizons. Knoxville fossils were found in a gritty 
greenish sandstone near the lowest portion of this pre-Monterey 
terrane, about 2 miles north of Zaca Lake. The higher portion seems 
to be the continuation of a formation in San Luis Obispo County that 


GEOLOGY. 


29 


has been considered upper Cretaceous and of one in southeastern 
Santa Barbara County that has been ascribed to the Eocene. Its 
age is therefore much in doubt. It may also include at the top part 
of the Vaqueros (lower Miocene), which overlies this doubtful ter- 
rane and of which the base has not been definitely determined. 

Structurally the strata included in this pre-Monterey group lie 
beneath the Monterey and upper Vaqueros, but though far older 
they do not bear so strongly the marks of intense folding as do the 
brittle Monterey shales. They are, however, steeply upturned, and 
the lines of folding, as in the case of the other formations, are in gen¬ 
eral in a northwest-southeast direction. 

TEJON, SESPE, AND VAQUEROS FORMATIONS, UNDIFFERENTIATED 

(eocene-miocene) . 

GENERAL STATEMENT. 

The Santa Ynez Range is mostly composed of a thick terrane of 
marine sediments equivalent to a part or all of the Tejon formation 
and the Vaqueros formation. The former is Eocene and the latter 
lower Miocene in age. This terrane comprises a continuous succes¬ 
sion of marine sediments of detrital origin, seeming to present no 
point at which an angular unconformity exists, although the line at 
the base of the coarse conglomerate containing the Vaqueros fossils 
doubtless marks a long time interval. 

In the preliminary report on the Santa Maria district 0 mention is 
made of the Sespe formation as being represented here, and a small 
area of it is shown on the map accompanying that report. The 
Sespe formation belongs to the Eocene or Oligocene and is a distinct 
formation above the Tejon and below the Vaqueros. It occurs ex¬ 
tensively in the Santa Ynez Mountains north of Santa Barbara, and 
an outcrop of blood-red sandstone in this range 3^ miles south of 
the Santa Ynez Mission was indicated on the outline map as belong¬ 
ing to the Sespe because of its lithologic resemblance to the typical 
rocks of this formation. This small area has, however, not been 
separately shown on the present map, as there is no good proof of 
its age. It is quite possible that the Sespe formation is represented 
in parts of this western portion of the range by rocks not recogniz¬ 
able on the lithologic grounds which are deemed sufficient for the 
determination of this formation in the vicinity of Santa Barbara or 
the Ojai Valley, to the east; or it may be that sedimentation was 
not operative in the western part of the range during Sespe time, and 
therefore that rocks of that age are lacking from the geologic section 
in this region. The amount of work done in the Santa Ynez Range 
does not warrant a full discussion of the structure and relations of 


a Bull. U. S. Geol. Survey No. 317, 1907, pp. 1-09. 

1784—Bull. 322—07-3 







30 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


its rocks stratigraphically below the base of the Monterey (middle 
Miocene) shale. 

Strata corresponding to the upper portion of the Tejon-Sespe- 
Yaqueros terrane have been recognized also in the San Rafael Moun¬ 
tains, where they are exposed at the base of the Monterey (middle 
Miocene), and it may be that the pre-Monterey rocks are in part 
equivalent to the lower portion of this terrane. The Yaqueros and 
possibly part of the Tejon are present also in the Casmalia Hills. 

LITHOLOGIC CHARACTER. 

The lower portion of the terrane is made up of a thick series of 
greenish-gray coarse and fine sandstones, many of them concretion¬ 
ary in character, interbedded with dark, fine-grained, thin-bedded 
shales in lesser amount. Toward the middle of the terrane the shale 
increases in amount, alternating with thin beds of sandstone. Much 
of the shale has a characteristic olive-gray color, and owing to its 
hard, gritty, brittle nature it makes excellent road material for the 
Santa Ynez Yalley. The shales and sandstones give place above 
the middle of the terrane to deposits of shallow-water character— 
coarse sandstone and a great quantity of coarse, in many places green¬ 
ish or reddish, gravelly conglomerate. This conglomerate contains 
abundant Yaqueros fossils and probably represents the base of that 
formation and a period of shallow-water conditions with which the 
Yaqueros began. The conglomerate gives place in turn to more 
•shale and sandstone, which continue to the summit of the terrane. 
At the top there is a conformable gradation into the Monterey (mid¬ 
dle Miocene) beds, the summit of the Yaqueros being marked by a 
calcareous zone in many places—as, for instance, southwest of Lom¬ 
poc, where the two formations are divided by a very prominent 
exposure of hard limestone. This limestone is quarried and used in 
the refining of beet sugar. Sandstone, shale, and conglomerate 
belonging to the Tejon-Sespe-Vaqueros terrane occur at the seaward 
end of the Casmalia Hills. They form a series conformably under¬ 
lying the Monterey (middle Miocene); but they are separated from 
beds of flint and shale that can be definitely assigned to the latter 
formation by an intervening horizon many hundred feet thick of 
soft, light-brown, clayey, alkaline shale that is almost invariably 
full of crystalline gypsum. Here the conditions existing during the 
period of transition from typical Yaqueros to typical Monterey sedi¬ 
mentation must have been very different from those prevalent over 
the areas occupied by the Santa Ynez and San Rafael ranges. Acidic 
volcanic ash is interbedded with the Tejon-Sespe-Yaqueros strata 
in the Casmalia Hills. The occurrence of the ash and the alkaline 


GEOLOGY. 


I 


31 


shale is mentioned by II. W. Fairbanks in the two quotations given 
under the heading 11 Previous knowledge of the geology, ” pages 12-13, 
and this author discusses them further in his paper there cited. 

STRUCTURE AND THICKNESS. 

Like all the Tertiary and pre-Tertiary formations of this region 
the deposits under discussion have been subjected to folding that 
has left none of them in an undisturbed attitude. But as they con¬ 
sist in large part of soft sandstone and conglomerate with inter- 
bedded layers of sandstone and clayey shale, they have not been so 
violently fractured and disturbed as much of the brittle shale of the 
lower portion of the Monterey (middle Miocene). The high ridge of 
the Santa Ynez Mountains from Point Conception eastward is formed 
by a great monocline in the sandstone of this terrane, dipping toward 
the sea on the south at an angle of about 30°. North of this ridge 
occurs a longitudinal depression in the range in which the folds of 
the beds are rather low; and still farther north, bordering the Santa 
Ynez Valley, these rocks are considerably disturbed, dipping in 
various directions and at all angles between 15° and the vertical. 
The general inclination of the beds on the north side, however, is 
northward, the structure of this part of the range, broadly viewed, 
being anticlinal. In the San Rafael Mountains the Vaqueros strata 
are steeply folded along northwest-southeast lines, in conformity 
with the overlying Monterey. A marked example of the way in 
which the soft, coarse conglomerate has been left little affected 
occurs in Buckhorn Canyon, where thick beds of this rock, probably 
the basal part of the Vaqueros, lie almost horizontal. 

The Tejon-Sespe-Vaqueros rocks have a thickness of at least 5,000 
feet in the Santa Ynez Mountains, and further work will probably 
allow these figures to be considerably increased. 

AGE AND FOSSILS. 

At least two distinct faunas are found in the Tejon-Sespe-Va- 
queros strata. The lower is characteristically Eocene, and similar 
to that of the Tejon formation of the type locality; the upper con¬ 
tains many of the species found at the type locality of the Vaqueros 
formation, which is the standard lower Miocene of the central Cali¬ 
fornia province. So far as is definitely known no species bridges 
the gap between these two faunas, either here or elsewhere in Cali¬ 
fornia, although the beds containing the two are apparently con¬ 
formable not only in the Santa Ynez Range but also locally as far 
north as Martinez, east of San Francisco Bay. 


32 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 

The following tables show the fossil if erous Tejon and Vaqueros 
localities and the species of fossils found at each. (See map, PL I, 
in pocket; and illustrations of fossils, Pis. XII to XXVI, pp. 126-154.) 

Tejon ( Eocene) fossils from the Santa Maria district , California. 


4507. 


Cardium brewerii Gabb (PI. XII, fig. 1). 

Codakia? sp. a.. 

Conus cf. hornii Gabb. 

Crassatellites collina Conrad (PI. XII, figs. 2a, 2b, 3). 

Dosinia elevata Gab£. 

Fusus occidentalis Gabb. 

Ficus mamillatus Gabb (PI. XII, figs. 5a, 5b). 

Glycymeris cf. veatchii Gabb var. major Stanton. 

Mactra cf. uvasana Conrad. 

Meretrix uvasana Conrad. 

Meretrix sp. 

Neverita? sp. 

Nucula truncata Gabb.. 

Ostrea idriaensis Gabb (PI. XIV, figs, la, lb). 

Pecten (Chlamys) yneziana Arnold (PI. XII, fig. 4; PI. XIII, figs. 6a, 6b)_ 

Phacoides cumulata Gabb (PI. XIV, fig. 2). 

Phacoides (Miltha?) sp.. 

Tellina?sp. 

Turritella (martinezensis Gabb var.?) lompocensis Arnold (PI. XIII, figs. 

5a 5b 8) 

Turritella uvasana Conrad (PL XII, fig. 6; PL Xlil, fig. 7). 

Venericardia planicosta Lamarck (Pl. XIII, fig. 4). 


X 

X 


X 

X 

X 

X 

X 


X 


X 

X 


X 



4509. 


4513. 4518. 


X 


X 


1 X 


.... X 
.... X 

x”! ”x 

.... X 
.... X 


X 


X 

X 


X 

X 

X 

X 


X 

X 

X 

X 


X 

X 


I 


4507. Just above San Julian ranch house, 1 mile southeast of bench mark 603. 

4509. Sharp turn in road in San Miguelito Canyon, 4i miles S. 20° W. of Lompoc bench mark 95. 
4513. South side of El Jaro Creek road, one-half milewest of bench mark 927. 

4518. Three miles north of Sudden, on north flank of 1,912-foot hill. 


Vaqueros (lower Miocene) fossils from the Santa Maria district, California. 



4478. 

4504. 

4508. 

4510. 

4511. 

4512. 

4514. 

4516. 

4517. 

4519. 

4520. 

4521. 

Balanus cf. estrellanus 
Conrad. 









X 

X 


X 


Cardium aff. quadrigen- 
arium Conrad. 


X 









Chione cf. mathewsonii 
Gabb. 





X 






Conus sp. 






X 






Crassatellites (?) sp. 





X 







Gasteropod, genus and 
species indet. 







X 

X 





Meretrix (?) sp. 












Modiolus vneziana Arnold 
(PL XV, fig. 2). 


X 










Mytilus cf. mathewsonii 
Gabb. 









X 

X 

X 

X 

Ostrea eldridgei Arnold 
(PI. XVI, fig- 2; Pl. 
XVIII, figs. 6a, 6b). 

X 

X 

X 


X 



X 




Ostrea, new species, near 
titan Conrad. 





X 

. 



Pecten vanvlecki Arnold 
(PL XVII, figs. 1,2). 

X 









Pecten (Lyropecten) bow- 
ersi Arnold (PL XVIII, 
fig. 5). 











X 

X 

X 

Pecten crassicardo Con¬ 
rad (Pl. XVIII, fig. 1).. 












Pecten lompocensis Ar¬ 
nold (PL XVIII, figs. 2, 
3, 4). 












Pecten magnolia Conrad 

(Pl. XVI, fig. 1). 

Pecten sespeensis var. 
hydei Arnold (PL XVII, 
fig. 3). 

X 

X 

X 

X 

- 

X 

X 



X 

X 

X 

Solen sp. 






X 


































































































































GEOLOGY. 


33 


Vaqueros (lower Miocene) fossils from the Santa Maria district, California —Continued. 



4478. 

4504. 

4508. 

4510. 

4511. 

4512. 

4514. 

4516. 

4517. 

4519. 

4520. 

4521. 

Terebratalia kennedyi 
Dali (Pl. XVII, fig. 4a, 
4b, 4c, 4d). 











. 

X 

Purpura vaquerosensis 
Arnold (Pl. XV,figs.la, 
lb). 


X 










Turritella sp. indet. 


X 










Turritella ineziana Con¬ 
rad (Pl. XVI, fig. 3). 






X 

X 

X 

X 




Turritella variata Conrad 
(young?). 























4478. Two miles south of Santa Ynez, on knoll just east of mouth of Ballard Canyon. 

4504. Three-fourths of a mile up ridge northeast of San Julian ranch house, 1£ miles east of bench 
mark 603. 

4508. El Jaro Creek, one-fourth mile east of Salsipuedes Creek, southeast of Lompoc. 

4510. Five miles north of Concepcion, one-fourth mile west of mouth of Escondido Creek. 

4511. Float on hillside along east side of Los Amoles Creek, 1 mile above El Jaro Creek. 

4512. .Ridge between Los Amoles and Salsipuedes creeks, 10J miles S. 33° E. of Lompoc bench mark 95. 
4514. About 10 miles west of Santa Ynez, on south bend of river H miles southeast of bench mark 552. 

4516. South of Santa Ynez Mission, 2J miles up Alisal Creek, at mouth of valley on east. 

4517. Three miles north of Sudden, on'north flank of 1,912-foot hill, above locality 4518, which is Eocene. 
(See p. 29.) 

4519. On ridge 2 miles east-southeast of El Jaro Creek, bench mark 603, one-half mile west of 1,111-foot 
hill. 

4520. West side of ridge between Los Amoles and El Jaro creeks, 1 mile west of bench mark 603. 

4521. Lime quarry 5 miles southwest of Lompoc. 


MONTEREY SHALE (MIDDLE MIOCENE). 


GENERAL STATEMENT. 

A great series of fine shales, largely of organic origin, overlies con¬ 
formably the coarse and fine sedimentary deposits of the Vaqueros. 
These shales make up the Monterey formation and are probably rep¬ 
resentative of the whole of middle Miocene time. The series is of 
great thickness and is doubly important, as the probable source and 
the present reservoir of the oil. The areal extent of the Monterey is 
not adequately represented on the map. It doubtless covers as one 
continuous sheet the whole basin between the Santa Ynez and San 
Rafael mountains, as well as a large part of these ranges, but it is con¬ 
cealed over considerable areas by later deposits, which are in many 
places very thin. The character, structure, and relations of the Mon¬ 
terey have been the chief subject of the present study. 

The name Monterey was given by William P. Blake a in the early 
fifties to an organic shale formation typically developed near Mon¬ 
terey, in central California. It is very extensive in the California 
Coast Ranges, being the “bituminous shale” described by Whitney 6 
as occurring at widely separated points north and south of the Golden 
Gate. Its age is generally taken as middle Miocene. It is the source 
of much of the petroleum found in California. The shale characteristic 
of this unique formation is not similar to ordinary clay shale, but is 
composed largely of the remains of minute marine organisms. .In an 


oProc. Acad. Nat. Sci. Philadelphia, vol. 7, 1855, pp. 328-331. 
b Geological Survey of California, Geology, vol. 1, 1865, p. 137. 










































34 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 


unaltered condition it resembles chalk, but is of siliceous instead of 
calcareous composition. 

The Monterey in the part of California treated here may be divided 
on lithologic grounds into two parts, although there seems to be per¬ 
fect conformity throughout the series. There is no definite dividing 
line to be drawn, but taken as a whole the lower half, composed 
chiefly of hard, metamorphosed, in places flinty shales, is distinct 
from the upper half, in which soft shale, giving evidence to the naked 
eye of its organic origin, is predominant. 

LOWER DIVISION. 

The fossiliferous limestone at the top of the Vaqueros is overlain 
conformably by hard calcareous and flinty unfossil if erous shale char¬ 
acteristic of the base of the Monterey. In places the limestone at 
the top of the Vaqueros is not well developed, but is replaced by a 
series of thin-bedded, in the main fairly hard, siliceous, calcareous, 
and somewhat argillaceous shales of coarse and fine texture, in which 
no well-defined line of demarcation between the two formations is to 
be drawn. The Vaqueros and Monterey terranes taken as wholes 
are distinct units, representing periods of deposition of entirely differ¬ 
ent character. As indicated by the rocks, deposition was continuous 
between the Vaqueros and Monterey and the change in character 
came suddenly, although less so in some places than in others. The 
general nature of the Vaqueros series is detrital; that of the Mon¬ 
terey is organic. The former contains many well-preserved mollus- 
can forms, the latter few. Close to the line between the two, beds 
predominatingly of a gravelly or sandy nature or those bearing fossil 
mollusks are considered part of the Vaqueros; those of a fine texture 
and of flinty or opaline or chalcedonic nature, part of the Monterey. 

Above the transitional limestone horizon between the Vaqueros 
and Monterey the lower half of the latter formation consists of a 
thick series of thin-bedded, hard, brittle, siliceous and calcareous 
shales, with local gradations on the one hand into beds of the hardest 
flint and on the other into soft diatomaceous earth. Near the base 
there is usually a horizon of black, brownish, or wax-colored flint 
in heavy beds one to several feet thick, and similar massive beds of 
peculiar sand-colored limestone with characteristic lamellar weath¬ 
ering. The greater part of the series is made up of brittle siliceous 
shale, usually much fractured and rather commonly crumpled, in 
beds averaging about one-half to 1 inch in thickness, in places alter¬ 
nating with thin shaly calcareous beds or massive strata of lime¬ 
stone. Pis. Ill, B, and VI, B (p. 46), show outcrops of typical flinty 
shale of the lower division. Beds of flinty shale or of pure flint are 
included here and there. The flint is of different colors—amber, black, 
milky, red, brown, etc.—and of different degrees of translucency. 
Much of it has been fractured and recemented with chalcedonic veins. 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. Ill 



A. CHARACTERISTIC EXPOSURE OF VOLCANIC ASH NEAR BASE OF MONTEREY FORMATION. 
At point where Cuyama River enters the Santa Maria Valley. Photograph by Ralph Arnold. 



UPTURNED AND CONTORTED SEMIFLINTY MONTEREY SHALE. 

On Sisquoc River, 5 miles east of Sisquoc. Heavy oil is exuding at a point immediately to the right 

of the man. Photograph by Ralph Arnold. 








































■ 











































* 









GEOLOGY. 


35 


It is in some localities banded with fine white laminae or with bands 
more translucent than the rest. These bands run parallel with the 
bedding, and commonly show intricate contortions. The flint frac¬ 
tures conchoidally. From the flint there is every step in the grada¬ 
tion through rocks of less hardness and flinty, compact character to 
soft white diatomaceous shale. The soft unaltered shale in which the 
constituent diatom tests are plainly to be seen occurs sparingly, how¬ 
ever, in the lower division. A striking example of its occurrence at 
that horizon can be found at the very base of the Monterey on the 
San Julian ranch, at the junction of El Jaro and Salsipuedes creeks, 
where it is pure, soft diatomaceous earth in thick beds, associated 
with flint and lime and overlying the hard fossiliferous, calcareous 
conglomerate of the Yaqueros. The specimen of analysis 3 (p. 45) 
is from this point. The varieties of shale are very numerous, but 
there is no departure from the general siliceous and calcareous types 
so peculiar to this formation. There is no common clay shale or slate 
derived from it, and only very locally is there an appearance of a 
sandy texture. In the San Rafael Mountains the series has a some¬ 
what different character, especially at the base, where a considerable 
amount of sandstone, in some places soft and in others quartzitic, is 
interbedded with the hard calcareous shales. Hard, coarse, yellow 
and grayish volcanic tuff of acidic nature is interbedded with the Mon¬ 
terey in the vicinity of Cuyama River (see PI. Ill, A), and elsewhere 
the lowest portion of the formation is marked by beds of tuff of local 
extent. At the east end of the Santa Rita Hills the Yaqueros grades 
into the Monterey through beds of coarse basic tuff composed of 
small fragments of glass and crystals of various kinds and of large 
fragments of pumice. Round bowlders or nodules of very fine grained 
basalt that look like volcanic bombs are included in this tuff. 

The series of hard shales of the lower division is commonly impreg¬ 
nated with bituminous material. The limy beds have almost uni¬ 
versally a bituminous odor and some of them contain pockets of tarry 
oil. The same is true of the flint with the difference, however, that 
the limestone is impregnated with petroleum, owing to its porosity, 
whereas the oil in the compact flint seems more commonly to be con¬ 
tained along lines of fracture or in cavities. The great mass of the 
hard, brittle shales has in general a similar odor or is discolored with 
oil. This hard shale series, especially the lower portion of it, and in 
places possibly the uppermost sandstone of the formation just below 
it, contains the principal oil-bearing zones in the developed fields. 
The fact that this shale is so brittle and fractures when folded has an 
important bearing on the storing of oil in this portion of the Monterey. 
The fracturing produces cavities in which the oil can collect while 
the softer unfractured shales adjacent remain more or less impervious 
to the oil. 


36 SANTA MARIA OTL DISTRICT, CALIFORNIA. 

UPPER DIVISION. 

The line of division between the lower and upper portions of the 
Monterey is rather arbitrary, yet if each portion is taken as a whole 
the lithologic distinction is marked, and the separation is made natural 
by the areal limitations of the outcrops of one or the other in various 
places. Where they are in contact a conformity between the two 
halves of the formation is evident and a gradation occurs from the 
porcelaneous and flinty shales of the lower part into the light-colored, 
earthy beds of the upper. Such is the occurrence, for instance, near 
the north edo-e of the hills 4 miles west-southwest of the town of 
Lompoc. 

The greater part of the upper division is made up of white or light 
chocolate-colored diatomaceous shale, usually of light weight and 
porous, but grading in places into heavier and harder, more compact, 
brittle, porcelain-like shale. The soft shale is extremely fine grained, 
rarely being at all gritty. The bedding is characteristically very thin, 
but where great masses of the soft white shale, which goes by the 
name of diatomaceous earth, occur, lines of bedding are usually 
indistinguishable, except here and there on thin projecting laminae 
produced by weathering, or on the upper surface of small cavities 
due to the eating out of less resistant patches. PI. IV illustrates two 
characteristic types of the soft unaltered shale. In the upper view 
it is massive, and bedding planes are almost indistinguishable except 
for lines brought into relief by weathering and erosion. In the lower 
view it is slightly more compact and lies in distinct platy layers. 
Major bedding planes from a fraction of an inch to several inches 
apart are distinctly apparent, and there is a further laminated struc¬ 
ture that enables the shale to be split into plates of extreme thinness. 
An artificial cut through somewhat disintegrated shale of the upper 
part of the Monterey is shown in PI. VIII, A (p. 78). The typical 
unaltered diatomaceous shale is pictured in PI. V, A. The small 
round diatom tests of which it is largely composed are faintly distin¬ 
guishable with the naked eye in the photograph. In general, both 
the softer and harder varieties of the Monterey shale, owing to their 
siliceous composition, do not give way readily to decomposition or 
weathering. Local chalcedonic lenses are to be found in this series 
roughly following the bedding planes in unaltered shale, as well as 
horizons of hard, porcelaneous, usually much-fractured shale; but 
the latter does not become predominant over the softer shale as it 
does in the lower division. 

The white chalklike deposits of this formation are not fully described 
by the use of the word shale in its ordinary sense. Especially in the 
massive deposits, where bedding is not very apparent, it has neither 
in composition nor lamination the character of ordinary shale. But 
this word has come into use in connection with the Monterey for lack 
of any other. The major portion of the formation, however, does 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. IV 




SOFT WHITE DIATOMACEOUS SHALE. 

A. Characteristic exposure north of Casmalia. B. Detail of weathering at Burton Mesa, east of Pine 

Canyon. Photographs by Ralph Arnold. 






U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. V 




DIATOMACEOUS SHALE. 

1 Typical soft white, unaltered specimen. B - Red brittle and heavy specimen; 
ypicai soti, w , by the burning of its hydrocarbons. 


metamorphosed 





GEOLOGY. 


37 


resemble shale in its thin stratification, the great difference being in 
the siliceous instead of argillaceous composition. Locally there are 
beds of clayey nature in the upper division which form a connecting 
link between the ‘ ‘ chalk rock/ ’ as the diatomaceous shale is colloquially 
termed, and common clay shale. Characteristic oval and lenticular 
yellow concretions of hard lime are commonly included in the shale 
of the upper division. They range in diameter from a few inches to 2 
feet or more. In many places they occur at irregular intervals and 
of irregular size along a bedding plane, locally displacing the ordinary 
shale and interrupting the continuity of not merely one bed but many 
thin beds. They are invariably elongated parallel with the bedding. 

Volcanic ash is interbedded with the soft shale of the upper divi¬ 
sion in the hills immediately south of Lompoc. It is very fine grained, 
soft, and uncompacted, and probably corresponds in composition to 
rhyolite. It somewhat resembles the pulverulent diatomaceous earth, 
but is easily distinguishable by its grayish color and grittiness. 

The upper portion of the Monterey, like the lower, is to a large 
extent impregnated with bituminous material. It is apt almost 
anywhere in this region to give out a bituminous odor when broken 
into or to show a brownish discoloration due to the presence of oil. 
In places the shale, otherwise white, is specked with minute black 
spots of bitumen. Thin sandy layers occur sparingly interbedded 
with the shale, and these almost without exception have absorbed 
considerable oil and have a dark-brown color and strong odor. But 
these beds of sand are very rare and make up no appreciable propor¬ 
tion of the series. 

The soft varieties of the Monterey shale are almost invariably 
alkaline and have a salty taste. They contain an abundance of 
salts easily soluble in water that form characteristic wooly coatings 
of efflorescence on the surface of outcrops. This is especially true 
near the summit of the formation, where a soft claylike gypsum¬ 
bearing shale locally marks the contact with the Fernando above. 
This gypsum is crystallized in plates along seams and bedding planes 
much like the gypsiferous clay of the Casmalia Hills, which is sup¬ 
posed to be Vaqueros in age. Zones of gypsiferous shale occur also 
at other places in the upper division of the Monterey, but it is not 
known whether there are any single horizons at which it is constant. 
Where the gypsum occurs the shale is usually of more argillaceous 
character and bears a closer resemblance to ordinary clay shales. 
The significance of this alkalinity in the Monterey is unknown. 
The organic shale is considered to be of marine origin in fairly deep 
water, and owing to the almost complete absence of all but the 
finest grained detritus the alkalinity can not be considered as proof 
of shallow-water or brackish-water origin. The salts may have 
some relation to the chemical changes involved in the production of 
petroleum. 


38 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

DIATOMACEOUS EARTH DEPOSITS.® 

The infusorial earth, diatomaceous earth, diatomaceous shale, or 
tripoli, as the same material is variously called, of which the upper 
division of the Monterey is chiefly composed, is of fairly pure quality 
in this region and of' considerable economic value, especially as it 
occurs in inexhaustible quantities close to transportation facilities. 
The areas of it are extended and the series of strata very thick. 
Deposits suitable for working occur in the hills immediately south 
of Lompoc; southwest and west of Lompoc; along the river east of 
Lompoc; in the northeastern and southeastern portions of Burton 
Mesa and over the Purisima Hills east of it; over wide areas in the 
Purisima Hills southwest, south, and southeast of Los Alamos; on 
the southern flanks of the Santa Rita Hills; 1J miles north of the 
Santa Ynez Mission; in smaller amounts near the east edge of the 
area mapped, a mile north of Santa Ynez River; underlying the San 
Antonio terrace south of Casmalia; over a wide region southeast, 
east, and north of Casmalia; on Graciosa Ridge, and in the region 
extending from the head of Howard Canyon to a point southeast of 
Sisquoc. The uses to which this material can be put are numerous 
and the demand for it is increasing. 

COMPOSITION OF THE MONTEREY SHALE. 

MATERIAL OF SHALE. 

The composition of the Monterey shale is of especial interest. 
One is able to see on examining the soft unaltered variety with a 
hand lens, or sometimes even with the naked eye, that it is full of 
small round dots ranging, to speak roughly, from 0.1 mm. to 1 mm. 
in diameter. These are the skeletons of minute marine organisms 
called diatoms. They are a low order of plants or algae having a 
framework of silica. They are locally so closely packed together 
that they seem to form the bulk of the deposit. In some of the rock 
they are so well preserved that the details of their structure can be 
made out with the aid of higher magnification. But elsewhere they 
appear crushed and almost unrecognizable. It is a question how 
much of the shale is formed of the diatom frustules that have been 
thus crushed. The shale in which the remains are well preserved 
and abundant is extremely soft and white and may be rubbed at a 
touch into a powder like flour. The round diatom disks are white 
and soft just like the matrix surrounding them, which looks as if it, 
too, were made up of diatom remains that had preserved their form 
less perfectly. Shale in which the remains are less prominent has 


a A more extended description of these diatomaceous deposits is published in “Contributions to 
Economic Geology, 1900” (Bull. U. S. Geol. Survey No. 315, 1907, pp. 438-447), under the title “Diato¬ 
maceous deposits of northern Santa Barbara County, Cal.” 



GEOLOGY. 


39 


the same appearance, as if formed of the same materials, but com¬ 
pacting and crushing seem to have gone a little further so as to obscure 
the organic remains. Almost all the shale of the upper division of 
the Monterey contains diatom remains where it has not undergone 
alteration into the hard varieties. The same is true of the soft 
shale wherever it occurs in the lower portion of the formation, the 
most notable example being at the very base of the Monterey on the 
San Julian ranch east of the junction of Salsipuedes and El Jaro 
creeks, where it is associated with hard flint and limestone immedi¬ 
ately overlying the fossiliferous limestone and conglomerate of the 
Vaqueros. There the shale is earthy, pure white, and full of diatoms. 

When the shale has undergone alteration and hardening into the 
porcelaneous and flinty varieties the constituent organic remains are 
usually obscured, but here and there even in these the impressions 
may be found preserved. Usually an examination under the micro¬ 
scope reveals scattering circular and oval areas, of slightly different 
composition or character from the surrounding rock, that look as if 
they might represent the forms of organisms. In speaking of the 
exposure of Monterey rocks between the mouth of Schumann Canyon 
and Lions Head on the southern flank of the Casmalia Hills, H. W. 
Fairbanks says : a “The basal portion of the series is composed chiefly 
of clear, flinty rocks, showing abundant remains of organisms visible 
to the unaided eye.” And in speaking of the harder varieties of 
Monterey shale in general of the Point Sal region he says: 6 “When 
examined with the hand lens much of the rock is seen to be thickly 
specked with little round dots, averaging, perhaps, a millimeter in 
diameter. Under the microscope * * * the circular areas did 

not appear as numerous as in the hand specimen, and were only 
faintly distinguished by clearer polarization.” 

Aside from the diatoms the rocks of the Monterey contain remains 
of minute Foraminifera, which have calcareous frames, and Radio- 
laria, which secrete silica to form their tests. The latter are present 
sparingly. The-common siliceous shale contains very little lime and 
no Foraminifera have been found in it in this district, although they 
have been reported from the typical Monterey shale elsewhere. 
R. M. Bagg c found 66 species belonging to 17 genera in chocolate- 
colored, soft, fine-grained shale of the same formation near Asuncion, 
San Luis Obispo County. J. C. Branner in the introduction to 
Bagg’s paper, describes the shale as follows: “The shale proper also 
varies; at some places it is flinty, at others it is somewhat sandy, 
and at still others it is soft and chocolate-colored, and contains an 
abundance of well-preserved Foraminifera. * * * The bulk of 

a Geology of Point Sal: Bull. Dept. Geology, Univ. California, vol. 2, No. 1, 1896, p. 9. 

b Op. cit., p. 10. 

c Miocene Foraminifera from the Monterey shale, California: Bull. U. S. Geol. Survey No. 268, 1905. 




40 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

this shale is made of diatom skeletons. * * * Even when the 

rocks are flinty they often contain good impressions of Foraminifera.” 
Foraminifera occur in the partially calcareous shales of the Santa 
Maria district, and in places the limestone is full of them. In some 
specimens they are perfectly preserved and various kinds may be 
easily seen with the unaided eye. In other places the limestone 
shows no trace of organisms; but it is the opinion of the writers that 
they have been present in such places and have lost their shape, and 
that foraminiferal skeletons account for a large part of all the Mon¬ 
terey limestone and for the calcareous portion of the limy shales. 
H. W. Fairbanks says in his paper quoted on page — that the lime¬ 
stone of the Point Sal region “ appears to be formed almost exclu¬ 
sively of minute organisms/’ 

Specimens representing different varieties of the Monterey shale 
and flint were sent to F. J. Keeley, of the Philadelphia Academy of 
Natural Sciences, who very kindly made examinations of them and 
reported regarding their diatom contents. (See Pis. XIX and XX.) 
He found diatoms plentiful in the unaltered earthy shale and less com¬ 
mon in the more compact shale and in the less pure, either gritty or 
argillaceous shale. Sponge spicules were common in all the samples, 
and in those last mentioned they were more abundant than diatoms. 
No examination was made of the indurated varieties. Mr. Keeley 
was unable to make more than a hasty examination, but on request 
he estimated roughly that the purest material contained from 5 to 10 
per cent of diatoms and that the soft shale in which fewer could be 
seen contained possibly 1 per cent. He found a few Radiolaria but 
no Foraminifera in the pure siliceous shale, diatoms and next to them 
sponge spicules being by far the predominant organic remains. 

C. S. Boyer, of the Philadelphia Academy of Natural Sciences, kindly 
identified the species of diatoms in two slides prepared by Mr. Keeley 
from the two purest samples of diatomaceous earth that were sent to 
him. Mr. Keeley says: “The lists made by Mr. Boyer cover only 
the species he saw in the slides sent him, and an exhaustive examina¬ 
tion of the material, which would require searching over, say, a hun¬ 
dred slides or more, would probably give a long list of species, many 
of which might not be seen more than once or twice in the course of 
such an examination.” Nevertheless, these lists probably indicate 
the commonest species. In the slide made from the shale at the base 
of the Monterey from the locality above referred to at the junction 
of Salsipuedes and El Jaro creeks Mr. Boyer found the following 
diatoms: 

Coscinodiscus marginatus Ehrenberg. 

Coscinodiscus marginatus var. intermedia Rattray. 

Coscinodiscus robustus Grev. 

Arachnodiscus (fragment). 

Diploneis? (fragment). 

Melosira sulcata Ehrenberg (rare). 


GEOLOGY. 


41 


Mr. Boyer says: “The-/deposit consists almost entirely of C. mar- 
ginatus and C. robustus of various sizes and often without rims. It 
is impossible, in certain cases, to distinguish between these two 
forms. The variety intermedia is between the two and was created 
by Rattray.” 

The second slide was made from soft shale of the uppermost por¬ 
tion of the Monterey, from the Pinal property on the east side of 
Pine Canyon, on the north flank of Graciosa Ridge. The following 
diatoms were found: 

Coscinodiscus oculus iridis Ehrenberg (abundant) (PI. XI, fig. XIX). 

Coseinodiscus marginatus Ehrenberg. 

Coscinodiscus marginatus var. intermedia Rattray. 

Coscinodiscus robustus Grev. (PI. XX, fig. 4). 

Coscinodiscus radiatus Ehrenberg. 

Coscinodiscus obscurus A. S. (PI. XX, fig. 2). 

Coscinodiscus nodulifer Janisch. 

Coscinodiscus heteroporus Ehrenberg. 

Coscinodiscus subtilis Ehrenberg (PI. XX, fig. 3). 

Actinoptychus undulatus Ehrenberg (rare) (PI. XX, fig. la). 

Arachnodiscus ehrenbergii var. californica (fragment). 

Lithodesmium eornigerum Brun. (PI. XX, fig. 16). 

According to Mr. Boyer this second sample consists chiefly of frag¬ 
ments of Coscinodiscus oculus iridis Ehrenberg, which is a larger and 
more delicate form than the one predominating in the first, and 
both he and Mr. Keeley comment on the peculiar absence of it there. 
The difference in the fauna in these different localities is of interest, 
inasmuch as the deposit represented by the first slide was at the base 
of the Monterey and that represented by the second near its summit. 

Besides the small organisms that have been described as forming 
a portion of the shale material, and the less abundant organic remains 
mentioned on pages 42-43, the deposits of Monterey age contain 
a considerable percentage of fine siliceous and aluminous matter, 
probably of detrital origin, in the shape of exceedingly minute clastic 
grains. The chemical analyses of specimens from different localities 
show a large percentage of alumina, the presence of which is prob¬ 
ably the result of fine argillaceous silt settling on the sea bottom 
to aid in the formation of the shale. The origin of the silica is more 
in doubt. There is no question of the presence of a large amount 
of siliceous diatom skeleton material, and the many fine-rounded and 
angular particles of quartz revealed by the polarizing microscope in 
the unaltered shale indicate that the sediments derived from shore 
areas carried quartz grains also, but there is no proof as to which of 
these sources supplied the bulk of the silica, of which the shale is 
mostly composed. Besides the recognizable diatom remains it is 
impossible to tell how much of the shale is composed of similar skele¬ 
tons that have been crushed beyond any semblance of their original 
form. Comparatively few forms are perfectly preserved, most of 


42 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

those observed under the microscope being only fragments, and this 
makes it probable that others are still more fragmentary and in a 
state of complete demolition. The likelihood, therefore, is that a 
greater proportion of the pure shale than 5 to 10 per cent, as roughly 
estimated by Mr. Keeley on the basis of visible forms, is composed 
of silica derived from diatoms. Radiolaria, which are scattered 
through the shale sparingly, have contributed somewhat to the organic 
silica. Whatever conclusion one should come to would apply to almost 
all of the soft unaltered shale of the siliceous type in the Monterey of 
the Santa Maria district, as this type is fairly constant. Locally it is 
varied by an increased proportion of argillaceous material, causing a 
greater similarity in appearance to ordinary clay shale, or by the 
presence of lime; but diatoms are visible in practically all of it and the 
general conditions of deposition seem to have been the same through¬ 
out. The conclusion is reached elsewhere (p. 47) that the same prob¬ 
able origin may be assigned to all the siliceous shales of the Monterey, 
whether hard or soft—or, in other words, to by far the greater part of 
the formation. 

The list of organic constituents of the shale is by no means exhausted 
by the small organisms of low order so far mentioned. Another 
important source of silica lies in the abundant sponge spicules, which 
are only second in number to the diatoms and which are scattered 
with remarkable persistency throughout the shale. In the slightly 
gritty beds of soft shale, which occur sparingly, these spicules even 
predominate over the diatoms, being possibly the cause of the grit- 
tiness. They seem also to be less easily obliterated than the fragile 
diatom shells and to have been preserved in places where slight alter¬ 
ation of the rock has destroyed the latter. One of the commonest 
and most characteristic features of both the unmetamorphosed sili¬ 
ceous and the calcareous shales is the presence of scales of fish, show¬ 
ing that fish remains found their way to the ooze at the ocean bottom 
in greater or less abundance. Locally the bones and nearly complete 
skeletons are also to be found. Delicate mollusk shells, usually of 
small size, are gathered thickly in some places in the Monterey shale, 
and at such points may be considered as constituting an appreciable 
proportion of the total volume of the deposit. As a rule they are 
crushed and poorly preserved, a fact that lends weight to the theory 
that a large part of the diatom frustules also have been destroyed. 
But mollusks are rare in the formation as a whole. Crab shells and 
claws are occasionally found, usually not whole but in small pieces, 
as if they had been subjected to conditions favorable to their destruc¬ 
tion before coming to rest. Seaweed impressions are not rare. In 
addition to organic remains of these kinds, the shales, especially the 


GEOLOGY. 


43 


less purely siliceous varieties, are usually full of small brown scales, 
spines, and fragments or impressions of nondescript shape which are 
of organic origin but which can not be recognized as belonging to any 
particular forms. Here and there, also, large bones are embedded 
in the deposits. They seem to be those of whales or other large marine 
vertebrates. 

Taken as a whole, the Monterey shale may well be called an organic 
formation. The practically complete absence of coarse sediments 
derived from erosion and the abundance of fossil organisms, espe¬ 
cially of siliceous skeletons, make it different both in appearance and 
composition from any other known formation of comparable thick¬ 
ness. The unaltered siliceous shale most nearly resembles chalk, but 
it contains only a small proportion of lime. Whether or not the 
organic remains compose more than half or as much as half of the 
deposit can not be stated. 

MICROSCOPIC APPEARANCE. 

Under the polarizing microscope little can be made out regarding 
the structure of the main mass of the soft shale and compact white 
shale. The groundmass seems to be made up of amorphous colloidal 
silica surrounding minute grains which are both crystalline and amor¬ 
phous, but the character of which can not be recognized. Embedded 
in this are numerous imperfectly angular or more rarely partially 
rounded crystal particles, probably of quartz. Many of the latter 
look as if they were due to secondary development rather than origi¬ 
nating as clastic grains. 

In the more flinty varieties the rock appears to have undergone par¬ 
tial and local crystallization of the silica throughout its mass. In the 
flint, in which there are alternating, usually crumpled bands of opaque 
light-colored flint and clear amber-colored or black flint, the opaque 
bands are composed mainly of amorphous material like that of the 
softer shale, but in a much more compact state, and the translucent 
bands are mainly crystalline aggregates. The opaque bands include 
crystalline particles and, locally, patches of crystal grains like those 
of the clear flint, and they are included longitudinally by intermittent 
bands of the clear flint. Furthermore, they are in many specimens 
of a patchy appearance, parts being less amorphous than others. 
The bands of the clear flint are composed chiefly of small grains of 
crystalline quartz, and these are surrounded by a finer grained aggre¬ 
gate of crystalline and amorphous particles. The quartz grains have 
neither the rounded outlines of waterworn grains nor angular crystal¬ 
line outlines, but are branching, and appear more like growths. Angu¬ 
lar patches of the amorphous silica, many of them showing signs of 


44 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


incipient crystallization, are included in the clear bands, giving a brec- 
ciated appearance. The bands are parallel with the bedding planes. 
They are commonly followed and more rarely crossed by veins of 
quartz crystals. 

The limestone is made up of granules of crystalline calcite, or cal- 
cite showing the beginnings of crystallization. Included in this 
extremely fine grained, uniform groundmass are larger but yet very 
small, irregular grains of crystalline calcite, and in places long spicules 
of the same. In some specimens the granules are more minute than 
in others and the included larger grains are fewer. In still others, 
crystallization has entirely altered portions into patches of large, 
intergrown crystals, leaving angular, unchanged patches sharply 
marked off, and thus giving an appearance like that of a breccia. 
The flinty calcareous shale has a minute granular texture, quartz 
grains both crystalline and semicrystalline being associated with those 
of calcite. The rock usually has light and dark bands parallel with 
the bedding, the light bands containing more quartz and having the 
calcite granules less close together than the darker bands. 

CHEMICAL COMPOSITION. 

The subjoined table comprises analyses of different specimens and 
varieties of Monterey shale from the Santa Maria district, with one 
(No. 5) here included for comparison, of a sample of white bitumin¬ 
ous shale from the type locality of the formation at Monterey, farther 
north on the California coast. 

The first three represent typical examples of the unaltered diato- 
maceous shale of the Monterey. Nos. 3 and 2, respectively, are analy¬ 
ses of the same samples that were found to be rich in diatoms when 
examined in slides 1 and 2 by Messrs. Keeley and Boyer, as mentioned 
on pages 40-41. Nos. 4 and 6 are analyses of samples from the same 
hand specimen, taken within 1 inch of each other, No. 4 showing the 
composition of unaltered white shale in which diatoms are visible, and 
No. 6 of the translucent, brittle, flintlike product of extremely local 
alteration. The next four indicate gradations in the products of the 
metamorphism. The last analysis (No. 11) represents limestone 
typical in lithologic appearance of the limestone of the Monterey. 


GEOLOGY. 


45 


Analyses of Monterey shale. 



Diatomaceous shale. 

Flinty shale. 

Lime¬ 

stone. 

1 . 

2 . 

3. 

4. 

5. 

6 . 

7. 

8 . 

9. 

10 . 

11 . 

Si0 2 . 

65.62 

72.50 
11.71 

2.35 

.32 

.83 

1.88 

9.54 

83.19 

80.59 

86.89 
2.32 

1.28 

1.43 

Trace. 

3.58 

4.89 

92.88 

86.92 

4. 27 

92.37 

2. 46 

97.02 

98.1 

Not 

det. 

Not 

det. 


AI 2 O 3 . 


Fe 2 03 (total iron)_ 







CaO. 





1.60 
Trace. 
2. 48 
5.13 

1.70 


27.86 
16.64 

MgO. 







Alkalies (Na 2 0,K 2 0). 
Ignition. 








11.00 




2. 74+ 
C0 2 












99.13 



100.39 


100. 40 

99.27 












1. Soft, white diatomaceous shale; Purisima Hills, 3J miles southwest of Harris, Santa Barbara 
County, Cal. Analyst, W. T. Schaller, 1907. 

2. Soft, white diatomaceous shale; Graciosa Ridge, 3 miles southeast of Orcutt, Santa Barbara 
County, Cal. Analyst, W. T. Schaller, 1907. Approximate analysis. 

3. Soft, white diatomaceous shale; San Julian ranch, at junction of El Jaro and Salsipucdes creeks, 
Santa Barbara County, Cal. Analyst, E. C. Sullivan, 1907. 

4. Soft, white diatomaceous shale; San Antonio terrace, 2 miles south of Casmalia, Santa Barbara 
County, Cal. Analyst, E. C. Sullivan, 1907. 

5. White shale; Monterey, Monterey County, Cal. Lawson, A. C., and Posada, J. de la C., Bull. 
Dept. Geology, Univ. California, vol. 1, 1893, p. 25. Specific gravity, 1.8-2.1. 

6 . Gray, glassy porcelain shale; from same hand specimen as No. 4. Analyst, E. C. Sullivan, 1907. 

7. White porcelain shale; region of Point Sal, Santa Barbara County, Cal. Analyst, II. W. Fair¬ 
banks, Bull. Dept. Geology, Univ. California, vol. 2, No. 1, 1896, p. 12. 

8 . Opaque flint; Point Sal, Santa Barbara County, Cal. Analyst, H. W. Fairbanks, loc. cit. 

9. Hard, black, clear flint; 1J miles west of Zaca, Santa Barbara County, Cal. Analyst, E. C. Sulli¬ 
van, 1907. 

10. Hard, black, clear flint; Point Sal, Santa Barbara County, Cal. Analyst, II. W. Fairbanks, loc. 
cit. 

11. Bituminous limestone; Redrock Mountain, northeast of Lompoc, Santa Barbara County, Cal. 
Analyst, George Steiger, 1907. 


ALTERATION. 


The differences in character and composition between the soft and 
hard varieties of the Monterey shale have been brought out in the 
foregoing discussion. The question arises, To what are these differ¬ 
ences due? It is difficult to give a decisive answer. The main differ¬ 
ences in the gradations from the soft to the hard shales lie in the 
siliceousness, compactness, hardness, and degree of crystallization. 
Taken as a whole the lower division is made up largely of hard shale 
and the upper of soft shale, but gradations from one variety to 
another within an extremely small space occur in both divisions. 
In some places a thick series of beds of similar character is marked 
off from a series of different character. Elsewhere a variation occurs 
bed by bed, or, in still other places, a single bed or lens of shale of 
one variety is included within another kind. The softer varieties 
contain at many points small lenses of hard, brittle, or semiflinty 
shale elongated parallel with the bedding, or strata in which lenses 
are strung along at irregular intervals, or single small beds com¬ 
posed entirely of harder material. In such occurrences there seems 
to be a gradation from one variety to the other, and the outlines 
of the hard layers are not regular or very definite. For example, 
the diatom-bearing shale of chemical analysis No. 4 and the glassy 
1784—Bull—322—07-4 

































































46 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


opaline rock of analysis No. 6 were samples taken from the same 
hand specimen within 1 inch of each other. The mass of the deposit 
from which' the specimen came was soft white shale belonging high 
in the formation and contained a rough layer, a few inches thick, of 
the harder material between two beds of the soft rock. 

The soft shale has been described in the preceding pages as ‘'unal¬ 
tered,” and in referring to the harder varieties different degrees of 
“alteration” have been mentioned, for the reason that the best 
explanation of the origin of the harder rocks appears to be that they 
are products of metamorphism of the soft variety. It is believed 
that the soft white and chocolate-colored organic shale represents 
the original state of the beds of the whole formation, and that a proc¬ 
ess of silicification and crystallization has caused the changes, this 
process having been aided possibly by structural disturbances and 
pressure. The beds of soft shale are usually found in attitudes only 
gently disturbed, whereas the harder shale is most commonly much 
folded and is invariably the component rock of folds where the 
forces have been especially intense. This fact may throw light on 
the problem of the alteration of the shale, and yet it may be simply 
the outcome of the removal of the softer portion of the formation 
in the regions of greatest uplift and disturbance. The chief agent 
in causing the change was probably infiltrating water carrying 
silica in solution. In some places the process may have been simply 
or largely infiltration in the extremely porous original shale and 
deposition of silica in the interspaces, thus giving rise to hardened 
and compacted irregular granular aggregates of the original amor¬ 
phous silica and the new crystalline silica combined, the result being 
an increase in the total percentage of silica. In more extreme cases 
the original material was probably partly taken in solution and rede- 
posited, being replaced almost entirely along bands or in spots, and the 
change being carried to a less extent along other layers and in other 
areas, or else the replacement was almost complete throughout. As 
the rock was rendered more compact in this process a shrinkage may 
have been the result, or the same volume may have been retained 
and the pores filled. That solution took place along with deposition 
seems to be shown by the almost complete destruction of the forms 
of organisms. 

It is possible that the differences in the shales may be original, the 
result of variation in the material deposited. Whole series of beds of 
different material might have been deposited, giving rise to harder, 
more siliceous rocks than the soft varieties, and the same material 
might have been locally deposited in thin beds or in lenses and 
nodules, or have been intermingled with the others to form the inter¬ 
mediate varieties. But it would be difficult to say what this mate- 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. VI 



Second ridge east of Figueroa Creek, 7 miles northeast of Los Olivos. Photograph by Ralph Arnold. 



B. SHARP DOUBLE FOLD IN MONTEREY SHALE. 

Looking east from point northwest of Zaca Lake; Zaca Peak in distance. Photograph by Ralph Arnold. 








GEOLOGY. 


47 


rial might have been, and the more or less completely crystalline 
character of the harder shales shows that metamorphism has taken 
place. The most plausible theory, therefore, is that the Monterey 
shale as originally laid down was fairly constant in character and 
that it has undergone alteration extensively, as well as very locally, 
through the agency of siliceous waters, the older portions of the 
formation, and possibly the more disturbed portions, having been 
most generally subjected to the change. The limestone has in 
places been altered after a fashion somewhat similar to that of the 
siliceous shales, being changed to marble, probably as the result of 
solution and redeposition. 

The Monterey rocks likewise show the result of contact metamor¬ 
phism to a very local extent in the vicinity of the diabase intrusions. 
The process seems to have been largely one of consolidation through 
baking. A limestone specimen obtained near the diabase intrusion 
north of Zaca Peak, in the San Rafael Mountains, gives an excellent 
illustration of shearing. The cal cite crystals have all been arranged 
parallel and greatly elongated, so as to give the rock a schistose 
structure. 

STRUCTURE AND THICKNESS. 

The Monterey has nowhere been left undisturbed. In places it 
has been but gently folded. Pis. IV (p. 36), VIII, B (p. 78), and IX 
(p. 80) show examples of moderate tilting. But at other places, as 
at that pictured in PI. VI, B (p. 46), it has been thrown into folds 
so sharp and closely spaced that the succession of the beds and 
thickness of the series are difficult to make out. The details of its 
structure are discussed under the heading “ Structure 7 ’ (pp. 76-78). 
The thickness of the whole series is at least 5,200 feet. Each of the 
two divisions comprises a maximum known thickness of 2,600 feet. 
No single complete section of the whole could be obtained. 

EVIDENCE OF AGE. 

A paucity of recognizable molluscan fossils is one of the prominent 
characteristics of the Monterey in this region, as in most others in 
the'Coast Ranges where it outcrops. Moreover, the other fossils 
that it contains are of little value in indicating its age. Its position 
in the geologic column is determined by the lower Miocene fossils 
found just below its base in the Vaqueros and by the upper Miocene 
fossils found at or near the base of the Fernando formation, which 
lies unconformably above it. 

The following two species of mollusks occur in the Monterey 
diatomaceous shale on the road just above the Pinal Oil Company’s 
office, southeast of Orcutt: Area aff. trilineata Conrad, Phacoides 
aff. acutilineatus Conrad. 


48 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 


METAMORPHISM OF THE SHALE BY COMBUSTION. 

At many different places in the Santa Maria district and elsewhere 
the oil-bearing shale has been burnt to a pink or deep brick-red color, 
or turned into a hard vesicular rock like scoriaceous lava, as shown 
in PL V, B, p. 36. This metamorphism is due to the combustion of 
the hydrocarbon content. Though the combustion is usually local 
in its effects, the number and wide distribution of the occurrences of 
burnt shale lend importance to the phenomenon. Such altered shale 
is of some value as indicating where the rock has been bituminous 
and where the conditions have favored the occurrence of seepages. 

LOCALITIES WHERE THE SHALE IS AT PRESENT BURNING. 

A number of localities have been observed at which combustion 
is at present or has been in recent years in progress within the Mon¬ 
terey shale. One of these is on the north side of Graciosa Ridge, 
south of the Santa Maria Valley, near the Rice ranch oil well No. 1. 
When this locality was visited by the writers early in the autumn 
of 1906, a fire was burning underground in the shale, causing a smoke 
of disagreeable odor to issue from the surface and making the ground 
hot over an area of many square yards. Oil was oozing up at various 
points near by, and the ground was heated in the neighborhood of 
all these seepages. . The holes from which vapor issued were coated 
with delicate crystals of sulphur. At the point where the burning 
was actually going on and all about in the vicinity, for a distance 
of several hundred feet in some directions, the shale was altered to 
a bright-red color, or baked almost to the hardness of compact igneous 
rock, or rendered vesicular like lava. 

There can be no doubt that this fire was supported by the bitu¬ 
minous material in the shale, and it was probably started by brush 
fires, though these had occurred a good many months before, as 
shown by the new growth of the bushes. It was said that there 
was a brush fire about January 1, 1906, which started the fire in the 
shale, and that futile attempts to put it out by dumping dirt to 
smother it had been made ever since that time. It seems likefy, 
however, that this same fire has been in progress for several years. 
This likelihood is borne out by other accounts. It is stated that 
sometimes during the course of brush fires on the hills sudden darts 
of flames may be seen at night from a considerable distance—the 
result of the setting on fire of gas escaping from the rocks. 

Other cases of burning in the shale have been observed in recent 
years at the San Marcos ranch in the Santa Ynez Valley, and at the 
mouth of Rincon Creek, on the coast near Santa Barbara, as de¬ 
scribed by H. C. Ford. a The phenomena exhibited resemble those 


a Bull. Santa Barbara Soc. Nat. Hist., vol. 1, No. 2, October, 1890. 






GEOLOGY. 


49 


of solfataras and have given rise to the opinion that volcanic activity 
is present in this region. This so-called “Rincon volcano” existed 
before 1855, being referred to in the Pacific Railroad reports; this 
shows that the burning has continued a long time. 

TYPICAL OCCURRENCES OF BURNT SHALE. 

Outcrops of burnt shale occur in eight or ten localities in the Santa 
Maria district. The best examples are at various places along the 
ridge of the Casmalia Hills from a point south of Schumann to 
Waldorf; on the north and south sides of Graciosa Ridge; and on 
Redrock Mountain 4 miles southeast of Los Alamos. In each of 
these regions every stage of alteration is exhibited, from the slightly 
discolored shale to hard slaglike rocks of varying shades of red and 
black. The area of altered shale in the different localities ranges 
from about a hundred square feet to a half a square mile or more, as 
at Redrock Mountain. In each the burnt rock is surrounded by unal¬ 
tered, usually soft, white, diatomaceous shales which in most places 
show the planes of stratification. At no point observed was a sign 
of stratification left in the baked shale. In every occurrence the shales 
in the neighborhood are bituminous and asphalt deposits are usually 
adjacent. 

The largest area of altered shale is on the summit and surrounding 
ridges of Redrock Mountain. This is the highest of the hills in the 
basin region between the San Rafael and Santa Ynez mountains, 
being 1,968 feet above the sea; the height of most of the summits in 
the vicinity is from 1,000 to 1,500 feet. Redrock Mountain seems to 
owe its prominence, at least in part, to the metamorphosed shale that 
forms its summit. Likewise, in the 800-foot hill on the southeast side 
of Schumann Pass, the capping of this same character, resembling 
volcanic rock, seems to have caused the topographic relief. The 
metamorphism in these localities probably took place a long time 
ago. At Redrock Mountain great deposits of asphalt are in places 
in contact with the altered shale, and there is a large area of shale 
impregnated with bitumen. 

DEPTH TO WHICH ALTERATION HAS EXTENDED. 

The depth to which alteration has extended below the surface in 
these occurrences is difficult to determine. A cliff of burnt shale 
50 to 100 feet high is exposed 4| miles due south of Guadalupe, and 
the difference of elevation of points in the Redrock Mountain neigh¬ 
borhood where the altered rock outcrops amounts to several hundred 
feet. That such metamorphism of the shale has not been solely a 
surface phenomenon is shown by the fact that burnt shale has been 
found at considerable depths in drilling. Mr. Orcutt, of the Union Oil 
Company, exhibited samples of red shale, coming from depths of 950 


50 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


to 1,040 feet below the surface in Hill well No. 1, in the Lompoc field, 
which are identical in appearance and texture with the burnt shale 
elsewhere. Traces of petroleum were associated with the upper 
stratum of burnt shale in this well. In numerous other wells in the 
Santa Maria field red shale, doubtless burnt, was found at depths 
ranging between 90 and 330 feet below the surface. The hardening 
consequent on the burning has in some places rendered the rock dif¬ 
ficult to pierce with the drill. 

LITHOLOGIC CHARACTER OP BURNT SHALE. 

The burnt shale exhibits all stages of change from a slight indura¬ 
tion and discoloration, due, probably, to oxidation of iron, to an 
extreme hardening and partial fusion. Where slightly altered, the 
normal white shale assumes a light-pink color. From this stage it 
passes through various shades of rose and brick-red and deepens in 
color to a reddish, bluish, or greenish black, or even a true black. In 
the advanced stages of change it becomes a rough, brittle, reddish, 
porous slag, like vesicular lava, or a very hard, compact, dark, and 
dull-colored rock, looking something like a compact igneous rock. 
An example of partly vesicular and partly compact burnt shale is 
shown in PI. V, B (p. 36). Burnt shale is not crystalline, but the 
texture is so variable as to give a patchy appearance to surfaces. In 
one place it may be compact and black, nearly full of irregular cavi¬ 
ties, surrounded by patches of different colors; in another, vesicular 
and reddish. Whereas the weight of the original shale is slight, the 
lighter varieties having a specific gravity less than that of water, the 
excessively burnt shale is very heavy. The material has evidently 
contracted to much less than its original volume, the angular cavities 
and irregular vesicles being one consequence of this contraction. 

Under the microscope the rock in the more advanced stages of alter¬ 
ation appears to have an exceedingly fine grained, amorphous, porous 
groundmass, discolored with reddish-brown or gray stains. Black 
filaments and dots appearing like carbonaceous material are common. 
Exceedingly minute rounded and irregular grains scattered through 
the whole, but forming no appreciable proportion of it, are the only 
portions visible under crossed nicols. They extinguish four times in 
a revolution of the field and are probably clastic quartz grains. 
These are characteristic of the unaltered shale as well. 

G. H. Eldridge a notes an occurrence of burnt shale near the old 
Blake asphalt mine, south of Graciosa Ridge. He says: “The shale 
now appears red, ashlike to hard and clinker-like, glazed, or silicified; 
bodies of bitumen contained within this have the appearance of a 
coke, as though derived from the solid fixed carbon of the petroleum.” 

a The asphalt and bituminous rock deposits of the United States: Twenty-second Ann. Rept. 
U. S. Geol. Survey, pt. 1, 1901, p. 428. 







geology. 


51 


The likeness of varieties of the burnt shale to volcanic rocks is indi¬ 
cated by the fact that Thomas Antisell, in his account of the geology 
of the Coast Ranges in the Pacific Railroad reports,® describes “scori- 
aceous” and “ amygdaloidal lava/’ “whitish-gray, hard trachytic 
rock,” “volcanic,” and “igneous rocks” in the region of Santa Ynez 
River, evidently having reference to the burnt shale. He considered 
these rocks to be eruptive masses, forming the oldest and axial rocks 
of the hill ranges, whereas they are part of the Monterey shale, which 
overlies the basement formation. He regarded the associated diato- 
maceous shales in some places, although not in others, as “magnesian” 
and “tremolite” rocks of igneous origin, and refers to the places 
where the shale is burning as examples of present volcanic activity. 

CAUSE OF THE ALTERATION. 

There can be little doubt that the burnt condition of the shale is 
in all places the result of heat produced by combustion of its hydro¬ 
carbon content. The phenomenon is confined to the Monterey shale, 
which is the source of a large part of the California petroleum, and 
to those regions in which this formation is extremely bituminous. 
The shale in many such places is impregnated with petroleum and 
the cracks partially filled with it. The areas of altered shale are 
almost invariably situated in the vicinity of oil seepages, which 
usually denote a fractured condition of the rocks such as would 
allow fire to spread and be supported. The observance of fires 
actually in progress in the shale and the changes that have taken 
place in the neighboring rocks—changes in every way similar to 
those in localities where no fire exists at present—give the best clues 
to the manner in which the shale has been baked in other places. It 
is difficult to conceive another source of heat sufficient to cause local 
baking of the shale in otherwise unaltered strata at a depth of 1,000 
feet below the surface in such a case as has been mentioned. Prob¬ 
ably there, as on the surface, it was due to ignition of bituminous 
material. It is probable that fire started in the petroliferous shale 
at the surface and threaded its way downward along cracks partially 
filled with bitumen. The failure to smother the fire in the shale on 
Graciosa Ridge, previously noted, indicates that such fires are able 
to survive with a small air supply. On the other hand, if the above 
theory is correct, it indicates that a considerable amount of oxygen 
may be present in the rocks at such a depth. 

In this connection it may be mentioned that the temperature in a 
well near the one in which the burnt shale was found was 152° F., 
at a depth of 3,600 feet. The cause of ignition may be kindled fires, 
lightning, or the spontaneous combustion of the hydrocarbons or 


a Explorations and surveys for the Pacific Railroad, vol. 7, 1857, pp. 65-72. 




52 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

surface vegetation. Many of the recent cases of burning are directly 
traceable to the first cause, but for those which may have taken place 
before the advent of man either the second or third cause will have 
to be invoked. 

RANGE IN TIME OF THE PHENOMENON. 

As already mentioned, the marked influence of the hardened shale 
on the topography in certain places indicates that it originated in 
those places a long time ago. The age of some of the burnt shale is 
further shown by the presence of numerous fragments of it at a 
depth of at least 10 feet below the surface in horizontal beds of Pleis¬ 
tocene age. These beds consist of sand, clay, and rough gravel, and 
form the low hills between Guadalupe Lake and the high hills to the 
west. The fragments of shale are little worn and evidently of local 
derivation, having possibly come from the cliffs already mentioned 
south of Guadalupe. The fact that the Monterey shale has under¬ 
gone this kind of baking in Pleistocene as well as in recent time indi¬ 
cates further that the accumulation of the oil and its dissemination 
in the surface rocks took place, or were taking place, before the 
latest orogenic movements in this coastal region. 

FERNANDO FORMATION (MIOCENE-PLIOCENE-PLEISTOCENE). 

GENERAL STATEMENT. 

The name Fernando was first applied by Homer Hamlin to a series 
of rocks overlying the Monterey in the San Fernando Valiev, Los 
Angeles County. The formation has since been recognized by 
Eldridge and Arnold 0 in the region of the Puente Hills, Los Angeles, 
and Santa Clara Valley oil districts, where it is a series of unaltered 
sedimentary rocks lying unconformably over the Monterey, and 
probably representing a portion of upper Miocene time, the whole of 
the Pliocene, and a part of the Pleistocene. Its lower portion is the 
equivalent of the Santa Margarita and Pismo formations, and its 
upper portion is contemporaneous with the Paso Robles formation, 
as these three are described by Fairbanks in the San Luis folio. 6 

In the region at present under discussion the name Fernando is 
applied to a similar formation that represents a large part of the 
Pliocene and probably includes the upper Miocene and part of the 
lowest Pleistocene. It consists throughout of a series of sandstone, 
conglomerate, and shale resting unconformably upon the Monterey. 
Unconformities also exist locally within the Fernando. It attains 
a thickness of at least 3,000 feet, but no one section exposes the whole 
series and it is probable that the formation includes a considerably 
greater thickness. It is widespread in the northern part of Santa 

a The Santa Clara Valley, Los Angeles, and Puente Hills oil districts, southern California: Bull. 
U. S. Geol. Survey No. 309. 1907, pp. 22-28. 
b Geologic Atlas U. S., folio 101, U. S. Geol. Survey, 1904.. 



GEOLOGY. 


53 


Barbara County, where it was deposited in the old basin between the 
Santa Tnez and San Rafael ranges. It covers up the Monterey 
over the greater part of the basin, and as its structure in most places 
there conforms approximately to that of the Monterey, it is a fairly 
good key to the folding that has taken place in this underlying 
formation. The relation between the Monterey and Fernando is of 
a somewhat perplexing nature. An unconformity in dip between 
the two was not to be definitely made out on examination of the 
exposed contact in any part of the central basin, because of the 
fact that the Monterey and Fernando were subjected practically to 
the same movements over a large part of the region. Lithologic 
similarity of parts of the Fernando to the Monterey is also an obstacle 
to their differentiation. But pebbles of Monterey shale and flint, 
showing here and there pholas borings and giving evidence of marine 
deposition, are abundant in the Fernando. In fact, the greater part 
of the coarse detrital material of the Fernando conglomerate is 

c 

derived from the Monterey, proving that its period of deposition 
was one of erosion in the previously deposited shale, that it followed 
the uplift above sea level of a portion of the Monterey, and that it 
was subsequent to the formation of the flint in that shale series. 
The importance of the break between the two is indicated by the 
change in character of the deposits from organic, probably deep¬ 
water sediments almost free from erosional debris to sandy and 
gravelly deposits derived from the wearing away of hard land areas. 
This change was hardly as marked as that occurring in the reverse 
order at the close of Vaqueros time, although it accompanied what 
was probably a greater time and structural break. The apparent 
structural conformity between the Monterey and Fernando at most 
places within the basin region is probably due to the previously 
almost undisturbed attitude of the shale upon which the Fernando 
was laid down and the subsequent disturbance of both formations 
at the same time. But remnants of the Fernando left around the 
border exhibit less conformity with the underlying Monterey, owing 
doubtless to the fact that the shale of the latter was upheaved around 
the edges of the basin to form the mountains bordering it during 
the period intervening between the close of Monterey time and the 
beginning of deposition of the Fernando. 

The chief importance of the Fernando in connection with studies 
of this oil field is derived from the facts that it hides the oil-bearing 
formation over a wide area; that it affords through its structure, 
however, a clue to the structure of the underlying Monterey; and 
that it acts as a reservoir for oil (Arroyo Grande field) and as a recep¬ 
tacle for escaping bituminous material. In the last-mentioned way 
it gives origin to asphalt deposits of economic value and to cappings 
of hard asphalt that may be of significance as an aid in the retention 
of the oil within the Monterey. 


54 SANTA MARTA OIL DISTRICT, CALIFORNIA. 

LITHOLOGIC CHARACTER. 

This formation is mapped as a unit, although it certainly rep¬ 
resents a long period during which sedimentation, continuous in 
the region as a whole, was locally intermittent and carried on under 
differing conditions, owing to the differential elevations to which 
the region was subjected. The stratum resting upon the Monterey 
in one place is apt to be absent in another, where an overlap of one 
or another stratum may occur. The lowest recognized Fernando 
rocks occur south of Sisquoc, where the Monterey is overlain by a 
bed of brecciated and waterworn shale derived from it and cemented 
by argillaceous sand, above which lies about 200 feet of fine sand, 
succeeded by a 50-foot layer of diatomaceous shale that is indistin¬ 
guishable from that of the Monterey. Above this shale the series 
grades up through about 600 feet of fine white and yellow sand and 
coarse sand, until a bed of conglomerate is reached. At other places, 
as south of Waldorf and south of Harris, the lowest stratum found 
at Sisquoc is either wanting or of minor importance, and beds of dia¬ 
tomaceous shale lie conformably over the Monterey shale, making 
the dividing line very hard to find. West of Waldorf the contact 
is marked for miles by a bed of brecciated Monterey shale of coarse 
and fine fragments, in places cemented into a hard amalgam by a 
paste of bituminous material. Here the overlying beds are made 
up of fine shale and sand and pebbly sandstone, which, though actually 
separated by an important unconformity from the Monterey, as 
indicated by the brecciated zone and the abundance of pebbles of 
that formation in them, are conformable in dip with the underlying 
beds. A still younger series of fossiliferous shale and sand marks 
the base of the Fernando 14 miles northeast of Divide, and also north¬ 
east of Schumann and northwest of Mount Solomon; and on the 
summit of the ridge in the vicinity of the head of Pine Canyon, 
halfway between the two latter localities, the Monterey is capped 
by what appears to be a part of the same series somewhat younger 
still. This shows that at the locality near the head of Pine Can- 
yon either an overlap of the late Fernando occurred on an old 
eminence of Monterey shale that was above the sea at the time of 
the deposition of the part of the Fernando immediately preceding, 
causing the omission on its summit of hundreds of feet of sedi¬ 
ments which were deposited around its base; or else the portion 
of the Fernando preceding this series was removed from above the 
Monterey during a period of erosion within Fernando time, this 
period being followed by subsidence. 

Along the ridge 1 mile southeast of Redrock Mountain, in the 
Purisima Hills, there is a capping of diatomaceous shale resembling 
that of the Monterey in every respect, but containing characteristic 
Fernando fossils. It was not suspected that this shale belonged to 
a formation distinct from the Monterey until the fossils were found. 


GEOLOGY. 


55 


It would be difficult to work out the limits of the area that this 
remnant covers. In all probability it is very small, and it has not 
been shown on the map. This shale here forms the base of the 
Fernando. A pebbly layer with constituent well-worn pebbles of 
Monterey shale embedded in sand has aided in the accumulation of 
asphalt on the summit of the ridge near by, where it probably marks 
the basal line of the Fernando formation. 

Above the soft diatomaceous or gritty shale and fine white sand 
that is common at or near the bottom of the Fernando the bulk of 
the formation is composed of rather loosely consolidated fine white 
and yellow sand and coarser gray sand that grades here and there 
into thick beds of loose conglomerate. The conglomerate is made 
of well-worn pebbles, mostly of flint and bard shale, embedded in a 
coarse sandy matrix. Locally the sand and conglomerate are ex¬ 
tremely hard, owing usually to the presence of a large number of 
mollusk shells from which a calcareous cement has been derived. 
The most prominent bed of conglomerate, and one that seems to be 
constant over the whole region, occurs from 800 to 1,000 feet up in 
the series (above the lowest horizon) just north of Canada de los 
Alisos, on La Laguna grant. What is probably the same bed is well 
exposed in cliffs west of Canada Laguna Seca, 1| miles south of the 
Los Alamos Valley. This loose aggregate of sand and pebbles in 
alternating strata of coarse and fine material is dominantly com¬ 
posed of the light-colored pebbles of Monterey shale. Pebbles of 
other varieties occur more sparingly. Above the conglomerate lies 
a stratum of limestone that is constant over the whole region and 
seems to mark a division in the Fernando. There are fwo or more 
massive beds of hard limestone interbedded with soft, gray, very 
alkaline, earthy material, making a total thickness ranging from 10 
to perhaps 50 feet. Its fossils indicate that it is of fresh-water 
origin, and possibly it marks the base of a fresh or brackish water 
series. The portion of the Fernando overlying this limestone prob¬ 
ably corresponds to the fresh-water Paso Robles formation of the 
Salinas Valley described by Fairbanks in the San Luis folio. In 
some places where this higher portion of the Fernando above the 
limestone has not been worn away, it is found to consist of little- 
consolidated beds of fine sand, gravel, and clay that look as if they 
might have been laid down in fresh water, but no proof of their 
origin has been found. Such beds are well exposed in the foothills 
of the San Rafael Range north of Santa Ynez, where they weather 
characteristically into cliffs at the summit of hills. A view of such 
an exposure is given in PI. VI, A (p. 46), which affords a good idea of 
the rough alternating beds of coarse material. No good lithologic or 
paleontologic criteria are known by which this series may be sepa¬ 
rated from the lower portion of the Fernando, and they are there¬ 
fore mapped as a unit. 


56 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


STRUCTURE. 

As has been stated, the Fernando is generally so nearly conform¬ 
able with the Monterey that it is difficult to draw a line between 
them on the basis of a discrepancy in dip. Nevertheless, it is in 
general true that folding has been gentler in the Fernando than in 
the Monterey. It would seem that the older formation had been 
disturbed in varying amounts, in some places severely and in others 
gently, during the process of uplift that put an end to its period of 
deposition. As a result the dips at the present time in the Fer¬ 
nando are apt to be less steep than in the Monterey, but folding has 
gone on largely along old lines, so that conformity in strike between 
the two formations is the rule. 

Wide, low folds are characteristic of the structure in the Fernando 
within the Santa Maria basin region. This is illustrated by the 
broad anticlines in this formation in the Solomon Hills, the broad 
anticline in the Purisima Hills, and the synclines in the Los Alamos 
and Santa Rita valleys, in which the dips range from 5° to 25° as a 
rule for a long way on either side of the fold and rarely become 
steeper than 30° or 35°. In places, as south and west of Sisquoc 
and west of Canada Laguna Seca, the beds are almost if not quite 
horizontal, but this is exceptional. Curves and plunges in the pre¬ 
existing low folds in the Monterey gave rise to structural basins in 
which the Fernando was deposited as a filling. Such was the origin 
of the oval area of Fernando sand covering the eastern portion of 
the Todos Santos y San Antonio grant. This basin is the westward 
extension of a great synclinal basin that runs from that localitv first 

o xJ 

eastward and then southeastward across the Los Alamos, La Laguna, 
and Corral de Quati grants and has determined the position of the 
Los Alamos Valley. The northern arm of this syncline slopes grad¬ 
ually up to the axis of the Solomon Hills, and the southern arm rises 
abruptly into the Purisima Hills, the slope on both sides conforming 
with the topography. The region of low slopes covered by parts of 
the Mission La Purisima and Santa Rita grants is a somewhat simi¬ 
lar wide synclinal basin filled with soft Fernando sediments. The 
Fernando is steeply upturned along the northeastern border of the 
Casmalia Hills, where it stands almost vertically in contact with 
much disturbed and in places overturned beds of the Monterey 
shale. It is upturned also where it rests against the serpentine 
north of Alamo Pintado Creek on the La Laguna grant, and south¬ 
west of Los Alamos it seems to dip very steeply under the brow of 
an overturn in the Monterey. In the San Rafael Mountains patches 
of Fernando deposits occur as remnants, and the beds in many 
places are steepty folded or turned completely on edge. They 
exhibit unconformity with the Monterey. In at least three places 
the Fernando is affected by faulting—a few miles west of Los Ala¬ 
mos, in the neighborhood of Cebada Canyon, and along the fault 


GEOLOGY. 


57 


% 


crossing Labrea Creek. In the first two the dip of the beds is mod¬ 
erate and the disturbance is not great. 

DISTRIBUTION. 

An idea of the distribution of the Fernando may be well obtained 
from the map (PI. I, in pocket), as it is not covered by so many forma¬ 
tions as the older series. It is much more widespread near the surface, 
however, than appears on the map, since it is probably present and 
hidden by only thin deposits over a great part of the area mapped 
as terrace deposits and alluvium. 

The general character of the Fernando is that of a filling. Its soft, 
loose, spreading sands, which preserve poorly evidence of low folds, 
form moundlike hills and broad valleys that convey the idea of a 
filled topography. But, on the other hand, harder beds and surface 
cappings due to hardening by iron oxide, which not uncommonly pro¬ 
duce sharp, square outlines, are marked features of the topography, 
as in the vicinity of Mount Solomon, at the head of Howard Canyon. 
On the northeastern border of the Casmalia Hills, between Schumann 
and Graciosa Canyon, a lime-hardened sandstone predominates and 
forms a prominent ridge. In the Santa Rita Hills the lines of structure 
that there curve around from a westerly direction to the southeast are 
brought out by the resistant limestone which supports the northeast 
flanks of the hills. The wide-stretching foothills of the San Rafael 
Range north of Santa Ynez have a character all tlieir own. They are 
formed of gravel, clay, and sand that have the appearance of belong¬ 
ing to a fresh or brackish water series, and they stand out with many 
bold faces that have been cut in the soft formation, as illustrated in 
PI. YI, A. Elsewhere the dominant character of the Fernando and 
its topographic forms are due to the soft sand which forms the major 
portion of the series. 

EVIDENCE OF AGE. 

At least five and probably six distinct horizons are recognizable in 
the Fernando by means of characteristic fossil faunas. The locali¬ 
ties at which these different faunas occur, named in their probable 
relative order, beginning with the oldest, are as follows: 

(а) South of Waldorf in soft shale; south and east of Sisquoc in fine sandstone. 

(б) “Sea-urchin bed,” Squires (Santa Maria Oil and Gas) lease; California Coast 

lease; south of Graciosa-Western Union wells; west of Harris Canyon; vicinity 
of Hill wells in the Lompoc field; and near head of Howard Canyon. 

(c) Waldorf asphalt mine, railroad cut 1 mile northeast of Schumann; Pennsylvania 

asphalt mine at east end of Graciosa Ridge; all in gray shale or fine gray sand¬ 
stone. 

(d) Waldorf asphalt mine; railroad cut 1 mile northeast of Schumann; Fugler Point 

asphalt mine; Sisquoc (or Alcatraz) asphalt mine; and points along north flank 
of Casmalia Hills, in coarse sandstone or conglomerate. 

( e ) East end of Folsom lease in soft sandstone. 

(/) Fresh or brackish water beds immediately west of the mouth of Canada Laguna 
Seca. 


58 


« 

SANTA MARIA OIL DISTRICT, CALIFORNIA. 

The beds at horizon a are of marine origin, are probably upper Mio¬ 
cene in age, and correspond in a general way to Fairbanks’s Santa 
Margarita and Pismo formations. Those at horizons b, c, d, and e are 
of marine origin, are closely related, belong at the base of the Pliocene, 
and are in a general way the equivalents of the middle Purisima 
and lower and upper San Diego formations. At horizon / are beds 
of fresh-water origin, probably representing Fairbanks’s Paso Robles 
formation and Lawson’s marine Merced formation. 

The following is a list of the fossils obtained from the Fernando: 

Fernando {upper Miocene-Pliocene-Pleistocene) fossils from the Santa Maria district , 

California. 



O 
r V 

t-H 

TT 

rr 

co 

r- 

rr 

rf 

r- 

»o o 

rr ^ 

Tf TT 

. 

r- 

GO 

tO 

GO 

CO 

GO 

! oo 

00 1 00 

rji 1 

00 

o 

C§ 

rr 

TT 

r-H 

'M 

05 

Tt< 

O 

to 

rf 

CO 

<M 

iO 

TT 

Actseon sp . 














... 


X 




Amphissa (?) sp 




X 

X 

X 














Angulus sp . 



















Area sp. a. . 






... 













Area sp. indet. 









X 




X 





... 

Area trilineata Conrad (PI. XXIV, 
fig. 5). 


X 

X 

X 

X 

X 

X 

X 

X 





X 





X 

X 

Astyris richthofeni Gabb (PI. XXIV, 
fig. 3). 

, 

X 

X 

X 


X 








Balanus cf. concavus Bronn. 






i- 







Bathytoma carpenteriana Gabb var. 
fernandoana Arnold (PI. XXIII, 
fig. 7). 

















Bathytoma cf. tryoniana Gabb. 




X 

X 

X 

X 

X 

X 

X 







| 







Bittium arnoldi Bartsch. 


















Bittium casmaliaensis Bartsch. 



















Cadulus fusiformis Sharp and Pils- 
bry (PI. XXI, fig. 8). 



















Calliostoma sp. indet. 




X 















Callista subdiaphana Carpenter. 



X 

X 

X 

X 

X 

X 







X 






X 

Cancellaria sp. a. 














Cancellaria crawfordiana Dali var. 
fugleri Arnold (PI. XXI, fig. 9). 
















Cardium meekianum Gabb. 





X 










X 




Cardium sp. indet. 


X 















Chione sp. 















X 




Chlorostoma (?) sp. 


X 

















Chrysodomus sp. T. 






X 

X 













Clidiophora punctata Carpenter (PI. 
XXIII, figs. 2, 3). 



















Crepidula princeps Conrad (PI. XXIV, 
figs. 1, 2). 


X 

... 

X 

X 

X 



X 



X 



X 

— 

X 

X 

Crucibulum spinosum Sowerby. 









Cryptomya ovalis Conrad (PI. XXII, 
fig. 7). 


X 



X 

x 

X 



X 

X 




X 






Cumingia californica Conrad (PI. 
XXIII, fig. 5). 















Dosinia ponderosa Gray (PI. XXII, 
fig. 8). 


X 


... 





X 





X 





Drillia graciosana Arnold (PI. XXI, 
fig. 18) . 


X 














Drillia johnsoni Arnold (PI. XXI, 
fig. 13). 



X 

X 
















Drillia waldorfensis Arnold (PI. XXI, 
fig. 12). 



















Echinarachnius ashleyi Merriam (PI. 
XXIV, figs. 6, 7). 

X 







X 

... 

X 

X 








Echinarachnius cf. excentricus Esch- 
scholtz var. (PI. XXIV, fig. 8). 




X. 







X 




Fusus sp. a. 


X 

X 















Fusus sp. b. 








X 

X 

X 









X 

Galerus~inornatus Gabb. 






X 

X 












Glycymeris cf. barbarensis Conrad ... 





X 




... 









Kennerlia(?) sp. 



X 

X 

X 

X 

X 












Ledaorcutti Arnold (PL XXII, fig. 9). 



X 








X 





Leda taphria Dali (PI. XXII, figs. 3a, 
3b). 















Lucapina cf. crenulata Sowerby. 





X 

X 











I 

Lunatia lewisii Gould (PI. XXI, fig. 3) 

• mm 

X 

... 

X 

X 





... 


1 



I i 






























































































































































GEOLOGY. 


59 


Fernando (upper Miocene-Pliocene-Pleistocene) fossils from the Santa Maria district , 

California —Continued. 



O 

CO 

i-H 

r- 

CM 

CO 

L- 

3 

t- 

tO 

TT 


c- 

T—1 

GO 

r 

tO 

00 

co 

$ 

!>• 

00 

Tfl 

TT 

00 

00 

O 

00 

8 

Oi 

'rp 

CM 

05 

CO 

o 

to 

CO 

CM 

to 

Lymnsea alamosensis Arnold (PI. 
XXI, figs. 6, 7) a . 















— 





Macoraa nasuta Conrad (PI. XXII 
eg. 5)... 


X 


x 

X 


x 



X 









X 

Macoma sp.... 



X 












Macoma cf. secta Conrad... 




X 




I-.. 











Mactra sp. 





x 

X 



X 


r" 








Miopleiona oregonensis Dali.... 




X 


x 


1 









■ 

Modiolus rectus Conrad.. 




X 

x 

X 




X 










Monia macroschisma Deshayes. 




x 












Muricidea sp. 





X 















Mya truncata Linne. 




X 









... 






Mytilus sp. indet.. 




x 


1 













Nassacaliforniana Conrad (PL XXIV, 
fig. 4).. 


X 



X 

x 

X 

X 

X 

X 

X 




1 


X 




Nassa waldorfensis Arnold (PI. XXI, 
fig- 17).. 



x 









Natica clausa Broderip and Sowerby 
(PI. XXI, fig. 16). 




X 

x 

x 














Neverita recluziana Petit (PI. XXI, 
figs. 14a, 14b, 15). 




x 

X 

X 













Ocinebra lurida Middendorf. 





X 













Ocinebra micheli Ford var. waldorf¬ 
ensis Arnold (PI. XXI, fig. 10). 




X 















Olivella biplicata Sowerby. 




X 


X 












Olivella cf. intorta Carpenter. 



! 



X 











Opalia anomala Stearns. 




x 

x 













Opalia varicostata Stearns. 




X 

x 














Ostrea veatchii Gabb (PI. XXIII, 
fig. 10) . 




X 

X 













...j... 

Ostrea possibly veatchii Gabb. 



X 














Panomya cf. ainpla Dali. 



::: 


x 













Panopea generosa Gould. 


X 


X 

X 

x 














Pecteh (Plagioctenium) near cerro- 
sensis Gabb. 



X 














Pecten (Patinopecten) healeyi Ar¬ 
nold (PI. XXVI, figs. 1, 2). 



1 

x 






X 








Pecten (Pecten) hemphilli Dali (PI. 
XXV, fig. 5). 





x 














Pecten (Chlamys) lawsoni Arnold (PI. 
XXV, fig. 3)1. 



X 

X 

X 

X 













Pecten (Patinopecten) oweni Arnold 
(PI. XXV, figs. 2a, 2b). 






X 








X 


Pecten (Pecten) stearnsii Dali (PI. 
XXV, figs, la, lb). 






x 












Pecten (Chlamys) wattsi Arnold (PI. 
XXV, fig. 4). 






X 














Phacoides annulatus Reeve (PI. 
XXIII, fig. 8). 


X 

X 

x 

x 









X 




Phacoides intensus Dali (PI. XXIII, 
figs. 9a, 9b). 


X 

X 














Phacoides nuttallii Conrad var. ante- 
cedens Arnold (PI. XXII, fig. 6)_ 


X 



x 


X 





0 






Pholadidea ovoidea Conrad (PI. 
XXII, figs, la, lb). 


X 

x ... 

X 

X 












Pholadidea (?) sp. indet. 











... 

X 


Platyodon cancellatus Conrad var.. 





X 














Pleurotoma (Borsonia) sp. a. 




x 















Pleurotoma sp. b.’. 





X 














Priene oregonensis Redfield var. an- 
gelensis Arnold (?). 





X 













Priene oregonensis Redfield (Young) 
(PI. XXI, fig. 2). 




X 1 









i 





Purpura crispata Chemnitz (PI. 
XXII, fig. 2). 


1 


x 















Saxidomus gracilis Gould. 


... 

1 


X 















Saxidomus (?) sp. a. 


*"l 

! 






X 










Scala sp. a. 




1 

X 














Sigaretus debilis Gould 


x'l 

xj 

















Siliqua cf. edentula Gabb. 


















Solen cf. sicarius Gould... 



X 

X 

X 

X 













Spisulacatilliformis Conrad var. alca- 
trazensis Arnold (PI. XXIII, fig. 6). 
Spisula sisquocensis Arnold (PL 
XXIII, fig. 1). 


...[ 

X 

X ! 














... 

1 











1 







a Fresh-water beds in the Fernando formation, 1 mile southeast of bench mark 425, Los Alamos 
Valley. 























































































































































































































60 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


Fernando (upper Miocene-Pliocene-Pleistocene) fossils from the Santa Maria district , 

California —Continued. 



4469 

r-H 

4472 j 

CO 

u- 

4474 

4475 

I- 

rr 

Tfi 

i-H 

00 

4485 

4486 ; 

4487 

00 

00 

4489 

4490 ! 

• 

r—H 

O 

-V 

o 

TJ1 

Tf 

4506 ! 

4523 i 

Ta.nes of la.c,ineat, a Ca,mentor 


X 

X 

X 

X 



X 

X 

... 

X 











Tapes st.a.leyi Ga.bh 






X 









X 

Tapes tenernma Carpenter (PI. XXII, 
fie 10) 




X 

X 

X 










Tellina, sp 


... 

X 












Tel 1 i n a; a.ff bod egen si s Hinds 










X 






Terebratalia occidentalis Dali (PI. 
XXII, figs. 4a, 4b) 






X 

X 

X 













Thalotia caffea Gabb (PI. XXI, figs. 
4, 5) 















• 




■*7 u / - -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 

Thra.eia. cf. trapezbides Conrad 



















Thya.sira, a.ff gonldii Philippi 




X 















Tresus nuttallii Conrad 




X 











X 




Tritonium sp. indet 




X 














Trochita radians Lamarck (PI. XXI, 
fig. 1) 





X 














Trochita sp. indet 

















X 

— 

Turritellacooperi Carpenter (PI. XXI 
fig- 11) 



X 

X 

X 

X 

X 

X 













Venericardia californica Dali (PI. 
XXIII, fig. 4) 



X 





























4469. One hundred yards northeast of California Coast oil well No. 3,1 mile east of Divide, and 3 miles 
southeast of Orcutt. 

4471. Alcatraz asphalt mine, 3 miles east of Sisquoc. 

4472. Pennsylvania asphalt mine, 3J miles southeast of Orcutt. 

4473. Waldorf asphalt mine, 3 miles south-southeast of Guadalupe. 

4474. Railroad cut 1 mile north of Schumann station. 

4475. Fuglcr Point asphalt mine, 1 mile north-northeast of Gary, at head of Santa Maria Valley. 

4476. Asphaltum layer above Monterey shale, near Folsom well No. 3, Santa Maria oil field, 3 miles 
southeast of Orcutt. 

4477. Near Folsom well No. 4, Santa Maria oil field, 2J miles southeast of Orcutt. 

4481. Five miles N. 30° E. of Lompoc bench mark 95, in prominent sandstone beds around Purisma 
oil wells. 

4485. One-half mile south of Sisquoc. 

4486. Echinarachnius ashleyi horizon, immediately west of Santa Maria Oil and Gas Company’s well 
No. 4, 2 miles southeast of Orcutt. 

4487. Immediately east of head of Howard Canyon, 4 miles north-northeast of Los Alamos. Echi¬ 
narachnius ashleyi horizon. 

4488. On ridge south of road about 2\ miles northwest of Blake. 

4489. Southeast side of La Zaca Creek, where it empties from steep canyon; at base of asphalt sand¬ 
stone in shale, 8 miles north of Los Olivos. 

4490. Four miles east-northeast of Los Alamos, on Cuaslui Creek. 

4491. Gully 2J miles west-northwest of Blake. 

4492. One and three-fourths miles S. 5° W. of bench mark 425 of Los Alamos Valley, one-half mile 
northwest of sink on top of ridge. 

4506. One mile southeast of summit of Redrock Mountain, along ridge, near 1,700-foot knob. 

4523. One mile due south of Sisquoc, in ravine. 


QUATERNARY. 

GENERAL STATEMENT. 

Three distinct classes of Quaternary deposits younger than the latest 
Fernando can be differentiated in this region, although it is difficult 
to distinguish between them areally. They are terrace deposits, dune 
sand, and alluvium, each one of which as mapped may possibly rep¬ 
resent more than one period of deposition. They are deposits of 
comparatively little thickness laid down unconformably upon the 
older formations subsequent to the greater part of the disturbance 
and deformation that has affected the region. 

TERRACE DEPOSITS. 

GENERAL DESCRIPTION. 

Terraces are common in this region and are among the most promi¬ 
nent topographic features. They are fairly even surfaces, invariably 

















































































GEOLOGY. 


(51 


inclined slightly toward the ocean or the line of drainage, and ranging 
in size from tens of square miles to only a few feet square. The more 
extended terraces fringe the coast line and the larger valleys and 
cover areas of low hills. The smaller ones are scattered over ridges 
and hilltops and along the smaller valleys. These terraces are cov¬ 
ered with a thin coating of sand and gravel, and here and there with 
clayey material. The distribution of the deposits is well shown on 
the map, with two general exceptions. In the first place, many of 
the strips of land along valleys mapped as covered with terrace 
deposits may not represent true terraces, as it is almost impossible 
to draw definite distinctions between such horizontally bedded val¬ 
ley fillings, true terrace cappings, and recent alluvium. All post- 
Fernando deposits in small valleys are therefore mapped with the 
terrace formation, and alluvium is shown only in the extended valley 
bottoms, where dividing lines between it and the terrace deposits are 
drawn arbitrarily. In the second place, owing to the lithologic simi¬ 
larity of the Fernando and the terrace-deposit sand and the similar 
surface appearance of these two formations, the attempt has been 
made to represent on the map only a few areas of the terrace sand 
overlying the Fernando. The Fernando is doubtless capped by ter¬ 
race deposits in many places, but it is usually impossible to tell 
whether this is true or not. The lines of contact between these for¬ 
mations are of necessity arbitrarily shown. 

This similarity causes much difficulty in places in determining 
whether the deposits belong to the Fernando or to the later epoch, 
and whether it is necessary to go through a great thickness of Fer¬ 
nando beds or only a few feet to reach the Monterey below. Where 
fossils, distinct lines of bedding, or tilted strata are present they are 
indications that the sand belongs to the Fernando. 

The terraces are found commonly at all altitudes up to 1,200 reet, 
and a few even as high as 1,400 feet. None have been definitely rec¬ 
ognized at a higher elevation. 

LITHOLOGIC CHARACTER. 

The material of the terrace deposits is usually sand and conglomer¬ 
ate, for the most part the former. The sand is medium grained and 
contains scattering waterworn pebbles. It is normally soft and 
grayish, but in many places compact, being stained a reddish yellow 
and hardened by iron oxide or filled with iron-stained concretions. 
In this surficially compacted state it forms hard cappings on hilltops 
and slopes. Round, bullet-like, iron-hardened concretions are char¬ 
acteristic of the derived soil. Over much of the surface of Burton 
Mesa and in other places this deposit occurs as loose, grayish sand, 
hardened locally by the action of rain water and various salts or 
oxide of iron. The conglomerate—or gravel, as it might equally well 


1784—Bull. 322—07-5 



62 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

be called—is composed of bowlders, pebbles, and fragments of Mon¬ 
terey flint and shale, besides pebbles of other rocks in smaller quan¬ 
tity. Some of the pebbles are very much waterworn, but in places 
the number of unworn fragments of shale almost necessitates the use 
of the word “breccia” in describing the deposits. Evidence of bed¬ 
ding is rarely prominent in the typical terrace deposits, but they 
invariably appear to lie horizontal, seeming to have been little dis¬ 
turbed by the uplift of the land that brought them to their present 
elevation. 

No fossils have been found in these deposits, but they contain 
numerous pholas-bored pebbles of Monterey shale, and in places, as 
on Burton Mesa, the Monterey shale itself, upon which the deposits 
lie, has been bored by these marine mollusks. 

Many of the cappings formed parallel with the surface through 
hardening by iron oxide have the appearance of being beds with 
appreciable dip, and are therefore misleading. The thickness of the 
coating of Burton Mesa is 25 or 30 feet and the cover of the typical 
terrace in other parts of the region has about the same thickness. 
Whether it attains a much greater development than this at any 
place is hard to tell. These shallow coverings hide considerable areas 
of the Monterey and obscure its structure, but most of the canyons 
that cut into the terraces reveal the presence of the oil-bearing for¬ 
mation beneath. The thickness of the coatings is not sufficient to 
make a serious difference in the depth to which it is necessary to 
drill for oil. The deposits are economically of importance as reser¬ 
voirs for the oil escaping from the Monterey shale, and thus they 
give rise to accumulations of asphalt. It is usually impossible to 
tell whether the sand that helps to form the asphalt is a terrace 
deposit or belongs to the Fernando. The terrace sand can not form 
as deep asphalt deposits as those due to the Fernando sand. 

In some of the valley fillings above mentioned, as for instance along 
Salsipuedes Creek, and at the west edge of the Santa Maria Valley 
between Guadalupe Lake and the Casmalia Hills, there occur hori¬ 
zontally bedded deposits of clay, sand, and gravel differing in ap¬ 
pearance from the terrace deposits and possibly differing in age and 
origin. A good example of an old valley filling which now forms the 
summit of a hill is shown in PI. IV, B (p. 36). It consists of a sandy 
and earthy material through which rock fragments and pebbles are 
scattered. It illustrates the usual unconformity of the post-Fernando 
deposits with the older formations. The low hills in the region of 
Santa Ynez are formed largely of horizontal beds of fine gravel 
unlike the Pleistocene deposits found elsewhere. These exhibit in 
one place an appearance of being tilted, though this may be due to 
cross-bedding. 


GEOLOGY. 


63 


ORIGIN. 

Most of the terrace deposits are probably of marine origin. This 
is proved in the case of the most typical deposits by the presence of 
the pholas borings already mentioned. The deposition was carried 
on in shallow water and much of the material was derived on the 
spot from the wearing away of the shore line of Monterey shale, the 
fragments of which were not always subjected to much polishing 
before being deposited and protected from agencies of erosion. 
These deposits give undeniable evidence of a great uplift of the 
coast during Pleistocene time. It seems most probable thbt the 
terraced surfaces resulted from marine planation along gradually 
rising shore lines and that the formation covering them represents 
the beach and shore deposits. The rise of the land was probably too 
rapid and the amount of sediment too small to allow much off-shore 
extension of the deposition. The material that may have been 
deposited in the deeper places determined by the depressions in the 
topography has since probably been largely removed by erosion. 
The terrace deposits themselves have been extensively eroded and 
in many places are left as mere remnants. Some of them have no 
doubt been subsequently added to by wind-blown sand. 

It is probable that some of the terraces and horizontal Pleistocene 
deposits along valleys have been formed by streams. Most of the 
valley fillings were probably laid down in this way. At the mouths 
of some canyons, as along the western side of Graciosa Canyon, 
Pleistocene deposits have been built up in the shape of detrital fans, 
which have since been carved into flat-topped, steep-sided blocks by 
recent streams. 

DUNE SAND. 

The prevailing northwesterly wind from the ocean has amassed 
great deposits of sand in places along the coast. The process has 
probably been going on all through the Quaternary period and it is 
hard to distinguish the older of the eolian deposits from those partially 
or entirely of marine deposition. The line of contact of these forma¬ 
tions as mapped is arbitrary. 

The greatest mass of dune sand occurs at the northwest end of the 
Casmalia Hills, where the gradual slope down to the sea from an eleva¬ 
tion of about 1,200 feet is covered by loose, yellow sand of probable 
eolian origin. This drifts about incessantly and is probably still in 
the process of collecting, being supplied from the long, low, open 
shore to the north and held in check by the bulwark of the Casmalia 
Hills on the south. This deposit has a thickness of several hundred 
feet. At its base along the coast is exposed a basal layer of large 
bowlders and horizontally stratified sand. The original slope of the 


64 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


hills was probably at least partly covered during the uplift of the 
coast by marine terrace deposits similar to those found elsewhere in 
the region, these being later buried by the gathering wind-blown 
sand. Recent marine shells are widely scattered over the surface 
of this sand, but are not considered by the writers as indicating its 
marine origin. They were probably carried there by Indians or 
birds. 

South of the Casmalia Hills, where the coast is open to the 
winds, sand dunes are continually forming and covering up the ter¬ 
race deposits. The sand is not retarded by an inland barrier, how¬ 
ever, as on the north of the hills, and no such vast deposit has been 
formed. The sand is continually being carried into the interior 
valleys and spread thinly over a wide area. 

ALLUVIUM. 

All the valleys of this region contain a certain amount of alluvial 
material and stream gravels, which reach in many localities a thick¬ 
ness of 50 feet or more. In some places the deposit is earthy, in 
others sandy earth, and in still others pure sand, gravel, or clay. 
It is as a rule horizontally stratified. Recent deposits of this charac¬ 
ter attain considerable extent in the wide valleys, but it is not easy 
to distinguish them from Quaternary deposits of different age or of 
somewhat different origin. They are mapped as distinct only in the 
larger valleys and the contact lines are arbitrary. Practically all 
the hills and valleys within the territory mapped have a covering 
of soil. 

IGNEOUS ROCKS. 

GENERAL STATEMENT. 

The formations in this region are chiefly of sedimentary origin 
but eruptive and intrusive igneous rocks of various ages appear. 
These are all basic in composition. Layers of volcanic ash high in 
silica interbedded with the Monterey are discussed with the sedi¬ 
mentary series (p. 37). The center for igneous rocks is in the region 
around Point Sal of which Fairbanks made a special study, and 
the statements here made in regard to the igneous rocks of that region 
are based largely on his description.® 

IGNEOUS ROCKS OF PRE-MONTEREY AGE. 

Fairbanks describes a small intrusion of basalt having a laccolithic 
appearance in the Knoxville (lower Cretaceous) shales north of 
Mount Lospe, in the Casmalia Hills, and a large neighboring area 
of spheroidal basalt that he is certain is older than the Monterey 

a Fairbanks, H. W., The geology of Point Sal: Bull. Dept. Geology, Univ. California, vol. 3, 1896, 
pp. 1-92, 










GEOLOGY. 


65 


and believes to antedate the Knoxville. It is closely associated and 
intermingled with bodies of diabase and gabbro. This complex 
forms Point Sal Ridge and the rocky headland of Point Sal. Another 
complex that he believes belongs in the Knoxville forms a long dike 
north of Schumann Canyon. It is an exceedingly complicated intru¬ 
sive mass of gabbro and peridotite that has been penetrated by later 
dikes of diabase, norite, gabbro, and intermediate types of rock. 

The areas mapped as Franciscan (Jurassic) are largely occupied by 
serpentine that was originally intruded in Franciscan strata. This 
serpentine may be older than the Knoxville, and the last-mentioned 
occurrence of gabbro and peridotite may be contemporaneous with it. 

Diabase was struck at a depth of 1,300 feet in the Pezzoni well 
No. 1, southwest of Sisquoc. It is a considerably altered rock com¬ 
posed largely of serpentine and plagioclase feldspar, with some augite, 
possibly a small amount of unaltered olivine, considerable magnetite, 
and several accessory minerals. This occurrence is of considerable 
importance as affecting the prospects for the production of oil in 
this neighborhood. The question arises whether this diabase has 
intruded the Monterey, as in the San Rafael Mountains, or whether 
it is a part of the older igneous formations, in which diabase is 
common. The fact that the rock is so much altered probably indi¬ 
cates that it belongs to a formerly exposed older formation upon 
which a fairly high portion of the Monterey shale series has over¬ 
lapped. It is hardly conceivable that an intrusion at such a depth 
in the shale could have undergone so much alteration. In either 
case, whether this diabase marks the base of the Monterey or whether 
the shales have been intruded by an igneous mass, the conditions are 
unfavorable for the discovery of oil in the immediate vicinity. 

IGNEOUS ROCKS INTRUDING THE MONTEREY. 

The youngest igneous rocks occurring in the Santa Maria quad¬ 
rangle and those of chief interest in the present connection are intru¬ 
sive in the Monterey (middle Miocene). Such are five small areas of 
diabase mapped by Fairbanks south of Point Sal and two areas of 
diabase in the San Rafael Mountains. The age of the two latter is 
somewhat in doubt, but the metamorphic and disturbed appearance 
of the Monterey shale in their vicinity indicates that they originated 
as dikes intruding the Monterey. The shale appears hardened and 
baked in the immediate neighborhood and narrow tongues of Mon¬ 
terey shale, certainly altered along the contact, extend into the mass 
on Tepusquet Creek. Along its edges appear patches of Aucella- 
bearing sandstone belonging to the Knoxville, which were probably 
brought up from below by the intrusion. The diabase in both areas 
is of dark-green color and coarse texture and exhibits sheared ser- 
pentinous facies. 


66 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


Another intrusion of probable post-Monterey age forms a single 
outcrop in the hills 7 miles northeast of Point Conception. It is a 
dike of basic porphyry related to basalt. On one side of the outcrop 
the bases of horizontally lying rough pentagonal columns are well 
exposed. It is not known whether the sedimentary rocks through 
which this is intruded belong to the Monterey or the upper part of the 
Vaqueros. 

GEOXjOGIC history. 

EARLIEST PERIODS. 

The general geologic aspect of the Santa Maria district is that of a 
region of comparatively recent geologic formations. Tertiary rocks, 
in places covered by Pleistocene deposits, are predominant, those 
of Cretaceous and Jurassic age less widespread, and older formations 
entirely absent. The Tertiary has received almost all the attention 
in the present study and little can be said of the history of the region 
previous to that period. The much-disturbed and metamorphosed 
Jurassic sediments (Franciscan), intruded by serpentine, form the 
basement of the whole region, but outcrop only very locally. In Cre¬ 
taceous time a considerable thickness of marine sediments was laid 
down, but these deposits were probably not greatly disturbed before 
the beginning of deposition in the Tertiary. To the present time they 
have remained unmetamorphosed and no more affected by moun¬ 
tain-making forces than later formations. Igneous intrusions, how¬ 
ever, took place at different times in the Cretaceous. 

EOCENE PERIOD. 

All the greater divisions of the Tertiary, with the possible excep¬ 
tion of the Oligocene, are represented by marine sediments, the 
major part of this time having been taken up by sedimentation. 
The relations between the Cretaceous and Eocene rocks have not 
been studied. Sedimentation began at some time in the Eocene 
not yet determined, in the southern portion of the region mapped, 
and continued nearly to the end of the Eocene, when it ceased for a 
period of unknown length. It was probably in the period just pre¬ 
ceding that of the deposition of the Eocene sediments that the forces 
began to work which caused the structural features south of the 
region where the San Rafael Mountains now stand to assume an east- 
west trend. In this way may have been formed the depression 
extending east and west across the region now occupied by the 
Coast Ranges, which afforded a basin of deposition for the Eocene 
and possibly a connection between the ocean and the basins in which 
strata of the same age were deposited in the interior. A large part 
of the Santa Ynez Mountains is composed of Eocene strata which 
have been lifted up along east-west lines of structure. The main 


GEOLOGY. 


67 


uplift, did not occur at the close of Eocene time, but it is probable 
that orogenic movements did bring to a close the period during 
which the Eocene sediments were laid down by raising the strata 
slightly above the sea and preventing for a time further deposition. 
How long this time was is not known, but it corresponds approxi¬ 
mately with the Oligocene. 

LOWER MIOCENE PERIOD. 

The movements immediately following the deposition of the 
Eocene caused no appreciable disturbance in the Eocene strata, and 
when sedimentation recommenced over the same area in lower 
Miocene time neither the old nor the new strata preserved any posi¬ 
tive evidence in their relative position that a time break had occurred. 
The great masses of coarse conglomerate forming the base of the 
lower Miocene portion of the group record a change to conditions 
of very shallow water, and the abrupt change of faunas indicates 
that a long time interval separated their deposition from that of the 
subjacent Eocene. It is most probable, however, that the post- 
Eocene movements, which were gentle, were also somewhat local, 
and that in portions of the Santa Ynez Mountains to the east of the 
region under discussion sedimentation was more nearly continuous. 
At about the close of the Oligocene period the Eocene basin was 
again depressed; deposition of sediments, almost entirely of detrital 
origin and very similar to those previously laid down, ensued in a 
widening area covered by the sea; and subsidence of the land gradu¬ 
ally continued. The Yaqueros formation, which resulted from this 
period of depression, represents the greater part of lower Miocene 
time. 

MIDDLE MIOCENE PERIOD. 

The middle Miocene (Monterey) shale formation is one of striking 
individuality, and conditions of unusual character prevailed during 
its period of deposition. At the beginning of middle Miocene time 
the land sank over a large part of the region of California now occu¬ 
pied by the Coast Ranges and fairly deep water conditions became 
prevalent. The wearing away of extended land areas ceased as they 
became submerged, and the material for the formation of coarse 
detrital deposits was no longer plentiful. Two varieties of deposits, 
which were largely, of organic origin, were the chief ones to be formed 
during the long period- that followed. These were the laminated 
limestones and the much more abundant siliceous shales. Silt of 
extremely fine grain, both of siliceous and argillaceous nature, was 
swept into the sea waters, probably from considerable distances, and 
settled down to form a considerable proportion of the deposits; but 
sand and other coarse detritus found their way only at rare intervals 


68 


SANTA MARIA OIL DISTRICT, CALIFORNIA.. 


to the main portions of the quiet sea bottom which was formerly 
the surface of the land and which had been given a comparatively low 
relief by the long period of erosion that preceded the submergence. 

During the period of transition between the Vaqueros and the Mon¬ 
terey, limestone was formed chiefly, but somewhat inclosed basins 
where deposits of alkaline mud were laid down apparently existed in 
places. Such a basin is indicated by the alkaline gypsiferous clays on 
the south side of the Casmalia Hills, probably representing upper 
Vaqueros. In some places, as, for instance, in the San Rafael Moun¬ 
tains, sandstone beds were formed early in Monterey time, probably in 
the neighborhood of locally unsubmerged areas. But later very little 
sand was deposited anywhere. Further submergence no doubt took 
place during the period, removing the sources of this sand and 
allowing to be deposited under fairly constant conditions a thickness 
of beds greater than a mile. It is not probable, however, that the 
depth of the sea was at any time as much as this, being more likely 
closer to half a mile. 

During the early part of Monterey time conditions were variable, 
calcareous and siliceous deposits alternating, probably as a result of 
alternating temporary predominance in the sea of organisms with 
calcareous or siliceous shells. As the period progressed the siliceous 
organisms became more predominant and remained so, making up a 
large fraction of the total bulk of the Monterey formation. It was 
an age of diatoms. These small marine plants lived in extreme 
abundance in the sea and fell in showers with their siliceous tests 
to add to the accumulating ooze of the ocean bottom, just as they are 
forming ooze at the present day in some oceanic waters. It is well 
known that diatoms multiply with extreme rapidity. It has been 
calculated that starting with a single individual the offspring may 
number 1,000,000 within a month. One can conceive that under 
very favorable life conditions, such as must have existed, the diatom 
frustules may have accumulated rapidly at the sea bottom and aided 
the fine siliceous and argillaceous sediments in the quick building 
up of the thick deposits of middle Miocene time. A principal obstacle 
to the rapid accumulation of the diatoms might be the limited supply 
of silica from which these alg*e derive the material of their tests. 
Other organisms with their shells and skeleton v ere ] so present 
to aid in building up the shale beds. They e Red olaria and 
Foraminifera; sponges with their spicule; > > v abundant; 

Crustacea; fishes, the remains of which are nuna * is m the shales; 
and mollusks with delicate shells, vdscii .v, 001 on, though poorly 
preserved. 

Volcanic eruptions, p *ssil !v .*<■ a;a; , broke out at different 
times during the latl a { ■>' i i Awer Miocene (Vaqueros) and 
the early part of th< n d lie Miocene (Monterey.) They may have 
accompanied movements tl a took place during the transition 


GEOLOGY. 


69 


period. Acidic volcanic ash of a rhyolitic type was ejected, and it 
settled in the ocean to form regular beds of considerable thickness 
and extent interstratified with the other sediments. The occur¬ 
rence of ash interbedded with diatomaceous earth that probably 
belongs fairly high in the Monterey formation indicates that these 
eruptions did not cease in the early part of middle Miocene time. 
Neither the centers of eruptions nor any lava equivalents of the ash 
have been found in the field. Similar eruptions were characteristic 
of the lower and middle Miocene for long distances north and south 
of this region. 

LATE TERTIARY AND EARLY QUATERNARY PERIOD. 

The Monterey period of deposition was brought to a close by 
orogenic movements which folded the shales and lifted them above 
the sea in many places. In some regions the folding was intense, 
the greatest disturbances accompanying the uplift of the mountain 
ranges to an altitude of thousands of feet. The San Rafael Moun¬ 
tains, which were upheaved at this time, probably extended along 
the lines of former mountains, and some smaller mountainous or 
hilly areas likewise, such as the Casmalia Hills and perhaps portions 
of the Santa Ynez Range, followed former zones of uplift. But for 
the most part the Santa Ynez Range was probably new. It is 
doubtful whether it was ever completely covered by Monterey sedi¬ 
ments, and its structure may have been determined by minor folding 
previous to the beginning of the Monterey, but it is probable that 
this range did not have any approach to its present proportions until 
after middle Miocene time. In other regions low, broad folds were 
formed during the post-Monterey disturbance and the strata were 
not upheaved to a great altitude; such was the case in parts of the 
basin region between the San Rafael and Santa Ynez mountains. 

After the formation of the middle Miocene shales they were 
intruded at several different points by basic igneous masses, mostly 
of the nature of diabase. The disturbance which put an end to the 
period was profound and this igneous activity was probably an 
accompaniment of it. The rocks were locally hardened by contact 
action in consequence of the intrusions. 

After an erosion interval, probably of comparatively short dura¬ 
tion, the land again sank, though not so extensively nor to such 
depth as in the previous subsidence, and a large part of the Santa 
Maria district, especially the lower regions, became submerged. 
The deposition of the Fernando followed, beginning before the close 
of the Miocene. Owing to differences in altitude and possibly also 
to local difference in the amount of subsidence, the deposition began 
in some places before it did in others. Over the areas in which the 
Monterey has been only slightly folded, the Fernando beds assumed 
conformable positions with it. In regions where the Monterey beds 


70 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


had been more highly tilted the later sediments were laid down 
unconformably. In places the first Fernando beds were of similar 
lithologic character to the Monterey shale, being deposited probably 
under similar conditions or else derived from the redeposition of the 
shale material. This similarity, added to the bedding conformity, 
caused the formations to appear as completely conformable and con¬ 
tinuous. But the presence in places of layers of brecciated Monterey 
shale at the base of the Fernando, and in places of true angular 
unconformities, proves that a period of erosion preceded the Fer¬ 
nando deposition. 

After the period of deposition of the finer sediments usually found 
at the base of the Fernando, shallow-water conditions prevailed. 
The deposits were almost entirely detrital, the product of erosion on 
land, much of the material coming from areas of Monterey shale. 
Fresh-water or possibly brackish-water conditions may have pre¬ 
vailed in the latter part of Fernando time. They certainly did for a 
time and locally, at least, when the brackish-water limestone beds 
were formed. 

MAIN QUATERNARY PERIOD. 

Downward and upward movements of the coastal region were 
probably in progress during the Fernando period, but were intensi¬ 
fied early in Pleistocene time, and disturbance of the strata along the 
lines influenced by the post-Monterey upheaval took place. In this 
way the mountain ranges were upraised in their present position and 
the Fernando became warped along the lines of further folding in the 
Monterey. 

After this uplift erosion set in and eventually removed the Fer¬ 
nando from some parts of the region over which it had formed a 
thick covering. The mountain regions were worn into rugged shapes, 
Santa Maria and Santa Ynez rivers developed graded valleys, and 
the sea planed off the coast extensively by cutting. During the same 
period, however, land building over this region was in progress as the 
result of differential movements of the coast. The great resultant 
changes of level in post-Fernando time, as indicated by the records, 
were a pretty general depression to a depth of 1,100 to 1,200 feet, and 
locally to at least 1,400 feet; and a later uplift to the present 
level. These movements were probably gradual and continuous, 
but not sufficiently slow to allow the formation of deposits of great 
thickness. During these movements the sea cut into the land as the 
water encroached and receded, forming terraces inclined toward the 
ocean, and beach and shallow-water sediments were laid down as thin 
coatings over the newly planed surfaces. These deposits were prob¬ 
ably formed as the land rose. During the periods of depression the 
streams built up deposits of gravel, sand, and clay at different levels, 
giving rise to extensive terraces and to filled valleys. Great deposits 


STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 71 

of wind-blown sand were formed also, and their formation is con¬ 
tinuing at present. During the late Quaternary the deposits and 
topographic forms resulting from all these processes have been carved 
by erosion; wide areas have been denuded of the thin Pleistocene 
capping; and in many places bits of terrace deposits are left merely 
as scattering remnants. 

STRUCTURE AND CONDITIONS AFFECTING TIIE PRES¬ 
ENCE OF OIE. 

THE ANTICLINAL THEORY. 

The anticlinal theory of oil accumulation assumes that the oil, 
being of lesser gravity, rises above the water present in porous 
rocks and collects at the highest possible points in upward folds, 
being there confined by impervious strata arching over the folds. 
The presence of water, according to this theory, is considered as 
fundamentally necessary for the carrying out of the process of 
accumulation in anticlines. 

The presence of oil in anticlinal folds was repeatedly observed in 
the eastern part of North America during the latter half of the 
nineteenth century. E. B. Andrews noted its occurrence along low 
anticlines in West Virginia and Ohio as early as 1861, and described 
this occurrence that same year,® and again, with more assurance of 
its wide application, in 1866. 6 

In 1863 the Canadian geologists, c in describing the oil springs 
immediately north of Lake Erie, noted their close relation to the 
anticlinal structure, and formulated the theory that the rise of the 
oil is due to the presence of water in the rocks. Their brief state¬ 
ment is as follows: 

Some of these springs appear to be on the line of the.great anticlinal which runs 
through the western peninsula, and subordinate undulations of a similar character 
will be found connected with others. The oil, being lighter than water and per¬ 
meating with it the strata, naturally runs to the highest part, which is the crown of 
the anticlinal, whence it escapes to the surface by some of those breaks which are 
usually found in such positions. 

Also in 1863 Sterry Hunt, to whom the above-cited conclusions in 
the Canadian report are probably due, described the oil of western 
Ontario as derived from low anticlines/ 

The following quotation is from an account written in 1885 by 
I. C. White* of his search for some method of determining the loca¬ 
tion of gas accumulations: 

In the prosecution of this work I was aided by a suggestion from Mr. William A. 
Earsenian, of Allegheny, Pa., an oil operator of many years’ experience, who had 

« Am. Jour. Sci., 2d ser., vol. 32, July, 1861, pp. 85-93. 
i> Am. Jour. Sci., 2d ser., vol. 42, July 1866, pp. 33-37. 
c Geology of Canada, Canadian Geol. Survey, 1863, p. 379. 
d Ain. Jour. Sci., 2d ser., vol. 35, March, 1863, pp. 169-170. 

« Science, vol. 5, No. 125, June 26,1885. 



72 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 


noticed that the principal gas wells then known in western Pennsylvania were sit¬ 
uated close to where anticlinal axes were drawn on the geological maps. From this 
he inferred there must be some connection between the gas wells and the anticlines. 
After visiting all the great gas wells that had been struck in western Pennsylvania 
and West Virginia, and carefully examining the geological surroundings of each, I 
found that every one of them was situated either directly on or near the crown of an 
anticlinal axis, while wells that had been bored in the syncline on either side furnished 
little or no gas, but in many cases large quantities of salt water. Further observation 
showed that the gas wells were confined to a narrow belt, only one-fourth to 1 mile 
wide, along the crests of the anticlinal folds. These facts seemed to connect gas terri¬ 
tory unmistakably with the disturbance in the rocks caused by their upheaval into 
arches, but the crucial test was yet to be made in the actual location of good gas ter¬ 
ritory on this theory. During the last two years I have submitted it to all manner of 
tests, both in locating and condemning gas territory, and the general result has been 
to confirm the anticlinal theory beyond a reasonable doubt. 

The anticlinal theory was found applicable, according to Red¬ 
wood,® by various investigators in the Eastern Hemisphere, in the 
Caucasian and Carpathian fields, in India, Persia, and Algiers, alid 
as stated by Lyman, 5 in some at least of the wells in Japan. Fur¬ 
ther credence has been lent to it by investigators in various parts of 
the world in subsequent reports on oil districts. It has, however, not 
been proved to be of universal application. 

ACCUMULATION OF OIL IN THE SANTA MARIA DISTRICT. 

In the Santa Maria and Lompoc fields the evidence indicates that 
anticlinal structure is favorable although probably not absolutely 
essential to the accumulation of oil. But whether or not this fact 
is explainable on the basis of the anticlinal theory as previously 
advanced, and as seemingly applicable to eastern fields, remains a 
question, for the reason that definite evidence is lacking regarding 
the presence or absence of water in the strata containing the oil. 
The fields of the Santa Maria district are not yet old enough to make 
it ascertainable whether water occupies lower levels in the same por¬ 
ous strata in which the oil is contained, or strata below those contain¬ 
ing the oil, and whether water will take the place of the oil on its 
exhaustion in the wells; or, on the other hand, whether the oil 
occurs unassociated with water in large amounts. What evidence 
there is throws doubt on the assumption that water is present in 
sufficient amounts materially to affect- the position of the oil in the 
strata. Although over a hundred wells have been sunk to depths 
ranging between 1,500 and considerably more than 4,000 feet in 
various positions relative to the axes of folds, water has been reported 
in only four wells at a depth of more than 1,000 feet below the surface, 
or below sea level, and in only a few wells below 300 or 400 feet. 
In other words, whatever water is present occurs in all but four wells 

a Redwood, Boverton, assisted by Holloway, G. T.: Petroleum and its products, London, 1st ed., 1896, 
vol. 1, pp. 44-46; also 2d ed., 1906, vol. 1, p. 112. 

*> Geological survey of the oil lands of Japan, Tokio, 1877 and 1878. 



STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 73 

near the surface, or at least considerably above the oil-producing 
zones. 

It may be questioned whether the presence of water is essential for 
the accumulation of petroleum in the upward folds of the strata under 
the conditions presented by the Santa Maria and Lompoc fields. 
Here the oil tends to rise to the surface and form seepages wherever 
channels of escape are offered. This is probably not due to hydro¬ 
static pressure, as there is no evidence that the water tended to 
rise in the same way; and it is just the opposite of the tendency 
ascribed to oil by upholders of the anticlinal theory, which would 
result in the oil descending and gathering in the synclinal troughs on 
subsidence or removal of the water. In the fields under discussion 
the oil is always intimately associated with gas. There do not seem 
to be, as a rule, separated stores of gas and oil, but the two are inter¬ 
mingled, or at least closely brought together, so that one is not usu¬ 
ally found without the other, although gas is sometimes found alone. 
The oil exhibits a tendency to migrate, as shown by its original con¬ 
centration from widely separated points of origin, by its surface seep¬ 
age, and by the energetic way in which it rises in the drill holes when 
a source of it is tapped. This migratory faculty may be ascribed 
entirely to the presence of the associated gas, which would cause the 
oil to fill every crevice offering a point of escape or a point of lodgment. 
If this is granted, it is evident that the points of accumulation of oil 
will be determined chiefly by the presence of cavities, large or small, 
offering a place for it to gather. Anticlines, being points of fractur¬ 
ing and in some places opening out of the strata, would afford likely 
places for the oil to lodge in those beds subject to fracture and for it 
to be imprisoned by overarching impervious beds. 

Aside from ideas as to accumulation of oil after such a fashion, the 
writers have come to the conclusion that in this region many of the 
“oil sands,” so called, are not true sands, but zones of fractured shale 
or flint offering interspaces in which the oil can gather. Beds of sand 
in the Monterey are scarce and thin. Some of the oil-producing zones 
are very thick, amounting to tens or even hundreds of feet. The oil 
occurs chiefly in the lower portion of the formation, where brittle, flinty 
shale is abundant; and as it is a noticeable fact that wherever these 
hard, flinty layers appear at the surface they are usually much more 
contorted and fractured than the associated softer shales, which are, 
in general, only folded and not broken, it seems likely that the same 
fracturing and resultant formation of an ideal reservoir for the oil 
takes place in the depths as at the surface. Where it is so fractured, 
the shale occupies a greater volume than before, showing spaces some 
of which are open and others partially or wholly filled with chalcedonic 
or bituminous material. The unfractured beds are more or less imper¬ 
vious to the rapid migration of the petroleum, and so act as barriers 
to keep the oil in the porous zones. 


74 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


It is therefore possible that in the Santa Maria district the gas pres¬ 
sure is the chief agent in giving the oil mobility, and that the condition 
of the rocks is the chief factor that controls the matter of where the oil 
is stored most abundantly. Hydrostatic pressure may not play an 
important part. The especially large accumulations in anticlines 
may be accounted for primarily by the cavities offered b}^ the strata 
along upward folds, and secondarily by the presence of less pervious 
beds arching over such folds and affording favorable conditions for the 
confinement of oil and gas tending to escape. Lesser stores of oil may 
occur at other points within the formation. 

INDICATIONS OF OIL. 

The chief criteria for judging as to the presence or absence of oil in 
appreciable quantities in this region have-been the attitude of the beds, 
their position in the series, and the surface indications. Other minor 
evidences of- a local nature have also been taken into account. In 
drawing conclusions from structural indications anticlines have been 
considered as the chief factors favoring accumulation, inasmuch as the 
oil appears to have gathered in them in a majority of the proved occur¬ 
rences in this district, other conditions being favorable. The conclu¬ 
sion has been reached that anticlines afford a fairly trustworthy clew 
to the location of the most important oil deposits. Close folding 
appears to play a part in this district in depriving the rocks of their 
oil, and excessive disturbance and fracturing is unfavorable to its 
retention. But, on the other hand, moderate folding would appear 
to be favorable, if not requisite, for the accumulation of stores of oil, 
and probably the most favorable conditions are afforded by anticlinal 
folds of such sharpness as to render the brittle rocks porous by frac¬ 
turing, but to leave less pervious arches of more elastic rock. 

The second criterion is the statigraphic position in the formation of 
the beds exposed over the area in which oil is sought. As has been 
before stated, the oil-bearing strata occur chiefly in the lower portion 
of the Monterey. Where the outcropping beds belong to the higher 
portion of the formation there is a greater likelihood that the under¬ 
lying oil-bearing strata have been able to retain their contents than 
where the lower strata have been denuded of the greater part of the 
overlying beds or where they are themselves exposed or partially 
removed. 

As regards the third criterion, the chief surface indications are 
afforded by the presence of seepages of oil or tarry material from the 
shales, by asphalt deposits, bituminous shales, and burnt shale. 
Asphalt occurs mainly in three ways—as a mixture of bituminous 
material with sand, due to the absorption by overlying sand deposits 
of seepages from the shale, as hardened fillings of asphalt in cavities 
along joints, and as excessively saturated shale. The burnt shale is 


U.S. GEOLOGICALSURVEY 
GEORGE OTIS SM ITH, DI RECTOR 


BULLETIN NO 322 PL. VI! 



SANTA MARIA 
VALLEY 

Ot a 


SANTA MARIA 
VALLEY 


PACIFIC 
OCEAX 
Sea level . 


GRACIOSA 

RIOGE 


SANTA MARIA VALLEY 
E Of Dal 


SANTA MARIA 
VALLEY 


SANTA MARIA 
n . VALLEY 


Sea le\’el 


Oil sands 


LOS ALAMOS 
VALLEY 


SANTA YNEZ *.2 
VALLEY 55 


TIONS ALONG LINES a-a to j-j on GEOLOGIC MAI 


Scale 12600 0 


5 miles 


LEGEND 


SEDIMENTARY ROCKS 


Q al 


Alluvium 



Terrace deposits 
• including alluvtum ejccept 
in huger valleys) 

UNCON FOR M / T Y 


>- 

(T 

< 

\l 

( UJ 
1 h 

Id 
I a 



mm 

Fernando formation 



Monterey shale 
f siliceous, bituminous,tliatnmuceous 
shales and. limestone) 





Tuff in terbe deled 
with the Monterev 



Vaqueros, Sespe, anil Tejon formations, 
undifferentiated 
(including some Monterey in Santa Inez Ranae- 
Sandstone, shale,conglomerate, and limestone) 



Pre -Monterey 

I safulstone,shale,and conglomerate > 
UNCONFORMITY 


Jf 


Franciscan formation. 
i chiefly serjyentine intruded in 
sandstoneRasfjer' and associated 
metamorplue glaucophaneschist 1 


Asphalt 


IGNEOUS ROCKS 


Post-Monterey inlrusives 
( intrusive diabase / 


b 

Pre 7 Monleiey inlrusives 

t intrusive basalt,diabase,gubbro, 
peridotite, and serpen tine .) 



1 


1 


1907 


PRE-TERTIARY? TERTIARY JURASSIC? CRETACEOUS- TERTIARY 


























































































































































STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 75 

the rose-colored or slaglike rock observed at many places in this and 
other oil-bearing regions within the Monterey formation. It is fully 
discussed on pages 48-52. It is the result of tire burning of the hydro¬ 
carbons that have impregnated the shale, and its presence therefore 
indicates where seepages have existed. 

GENERAL STRUCTURAL CONSIDERATIONS. 

The area comprised within the limits of the Lompoc and Guadalupe 
quadrangles has been subjected to two systems of forces acting 
obliquely to each other, the one producing structural features which 
trend northwest and southeast, the other those which trend east and 
west. (See PI. VII.) The system causing the northeast-southwest 
structure was probably the older and dominating one, as it brought 
forth the highest ranges and most extreme folding and conformed 
with the great system which has determined not only the Coast 
Ranges of California but the western border of the North American 
continent. The forces producing the east-west features, although 
exceedingly effective from the west end of the Santa Ynez Range east¬ 
ward to the region south of the end of the San Joaquin Valley, were 
not so far-reaching as those of the other system and probably began 
to exert themselves at a later date. 

That portion of the area under discussion which lies to the north¬ 
east of the Santa Maria Valley is dominated almost completely by 
structural lines trending northwest and southeast; in the extreme 
southern portion lines trending east and west prevail. The region 
between these two areas is occupied by folds and faults, some of whose 
component parts exhibit allegiance to one system and some to the 
other, but whose resultant trend is intermediate between the two. 
In a general way the lines of disturbance as well as the topographic 
relief within this central province radiate fanlike from the point of 
divergence of the Santa Ynez and San Rafael ranges east of the town 
of Santa Ynez. 

The forces acting throughout the region have more often found 
equilibrium in the production of folds than in adjustment by faulting. 
Several important faults are recognizable, however, and doubtless 
others will be revealed by detailed work, especially in the San Rafael 
Range. There is evidence to show that forces have acted intermit¬ 
tently along the same general lines throughout a long period of time. 

DETAILED DISCUSSION OF STRUCTURE. 

In the field study of the structures of the formations and in the 
present discussion special attention has been paid to the structure of 
the Monterey shales, because that formation has apparently given 
origin to the petroleum and in it the bulk of the oil is stored. 


76 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


For convenience the two quadrangles will be divided into the three 
naturally separated portions outlined in a preceding paragraph, viz, 
the region of the San Rafael Range, which includes all of the territory 
northeast of the Santa Maria Valley and a line extending southeast 
of its head; the region of the Santa Ynez Range; and the province 
of low hills and shallow valleys intervening between the two moun¬ 
tain masses. The reading of the following paragraphs describing the 
structure of various areas should be accompanied by reference to the 
map. (PL I, in pocket.) For the sake of compactness the conclu¬ 
sions as to the possibilities of productiveness of the Monterey shale 
have been stated, together with the description of its main structural 
features. 

It must be remembered that in regions of great disturbance such as 
the shales have undergone in some parts of the area it is difficult to 
represent by single lines the complexity of the structure. Some of 
the lines, therefore, mark zones of folding rather than single definitely 
continuous folds. The dotted lines of structure are purely supposi¬ 
tional. 

REGION OF THE SAN RAFAEL MOUNTAINS. 

AREAS OF ROCKS OLDER THAN THE MONTEREY. 

Whatever succession of beds or structural conditions may once 
have existed in the Franciscan formation (Jurassic?) in this district, 
they have been largely obliterated by the successive folding and 
crushing to which these rocks have been subjected in the long period 
of time since their first uplift. The shales and sandstones mapped as 
pre-Monterey, especially where the beds alternate, have preserved the 
folds well, but except on North Fork of Labrea Creek and along Sis- 
quoc River no effort has been made to work out the structure of this 
series. 

AREAS OF MONTEREY AND LATER FORMATIONS. 

FOLDS. 

Considered as a whole the Monterey has been thrown into a series 
of anticlinal and synclinal folds striking about N. 50° W., and appar¬ 
ently plunging, in the main, toward the northwest. Great variation 
exists in the relative steepness of dip along these folds, but it is evident 
that the compressive forces producing them were of much greater 
strength in the southeastern part of the area, between Bone Mountain 
and Round Corral Canyon and thence southeastward into the region 
of Zaca Peak. Here the folds become so compressed and in places 
overturned that it is difficult to trace them. PI. Ill, B (p. 34) and 
VI, B (p. 46) give an idea of the closeness of the folding. In contrast 
with this constricted portion is the broad series of folds which extend 


STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 77 

rather uniformly along the northeastern border of the area, and de¬ 
velop toward the southeast into the syncline crossing Tunnel Canyon 
and Horse Gulch just north of Sisquoc River. The high, broad ridge 
between Bone Mountain and Manzanita Mountain is composed of 
Monterey shale, which lies approximately flat, and toward the north¬ 
west becomes one arm of the great syncline which extends through 
Goodchild’s ranch on Labrea Creek and is traceable almost to Colson 
Fork of Tepusquet Creek. A similar syncline, possibly the same, 
extends from Colson Fork northwestward across Tepusquet Creek to 
the margin of the Lompoc quadrangle. The northeastern arm of this 
fold forms the high ridge extending along the southwestern side of 
Buckhorn Canyon. 

It is possible that the pre-Monterey rocks north of Bee Rock Can¬ 
yon plunge down monoclinally under the Yaqueros in a fold at right 
angles to the wide anticlinal fold that exposes the former. Such a 
plunge would be apt to give rise to the northeast-southwest table 
between Bone Mountain and Manzanita Mountain that interrupts the 
structure to the northwest and southeast, and this table may, there¬ 
fore, represent a buckling across an otherwise continuous structure. 

Southwest of Los Coches Mountain one or more folds are over¬ 
turned, but the northwestern extensions of these folds have not been 
examined. 

The region southeast of Round Corral and Asphaltum creeks is 
occupied by several sharp folds which strike in a general northwest- 
southeast direction. Overturning is not uncommon in this series of 
folds, one notable example being an anticline on the southern flank 
of Zaca Peak. West of Round Corral Creek the structure lines bow 
around from a northwesterly to a westerly or west-southwesterly 
direction, the folds at the same time becoming less compressed and 
the conditions for the retention of the oil in the basal sands of the 
hard shale series correspondingly better. 

FAULTS. 

There is strong evidence of a fault zone passing north of the nar¬ 
row area of intrusive rock north of Zaca Lake, and thence north¬ 
westward as far as the head of Rattlesnake Canyon. The resultant 
downthrow along this zone of displacement is on the southwest, 
probably amounting to a good many hundred feet toward the east 
edge of the Lompoc quadrangle. Toward the northwest this fault 
apparently dies out or merges into a sync line. 

Just east of Los Coches Mountain there may be another fault 
which brings* up the uppermost Vaqueros on the north. A third 
fault between the Pliocene and Monterey may extend from a point 
near the mouth of Round Corral Canyon to Labrea Creek. 

1784—Bull. 322—07-6 


78 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 


Faults also occur along the Franciscan-Fernando contact in the 
region northwest and southeast of Figueroa Creek, but the resultant 
throw was not determined. A depositional contact is clearly exposed 
along this same line just northwest of Alamo Pintado Creek. 

EVIDENCES OF PETROLEUM. 

Despite the great development of folds within the Monterey area, 
only here and there do seepages of asphaltic material occur. It 
would seem that the fractures produced by sharp folding would give 
adequate channels for the escape of petroleum, and it is surprising 
to find so few seepages. The best developed of these is on Labrea 
Creek at and near its junction with Rattlesnake Canyon, and is 
typical of the localities noted north of Sisquoc River. The oil seep¬ 
age is associated with small springs of strongly saline and sulphurous 
water, and the oil has exuded along the bedding planes of the Mon¬ 
terey shales, here thrown into a pronounced anticline which has been 
flexed in such a manner as to open out the laminae of the shale and 
thus give better opportunity for the passage of oil. Two wells have 
been sunk here, but they are shallow and offer no additional data. 

The following is a brief statement of the asphalt seepages and brea 
deposits occurring in the San Rafael Mountains: 

1. Branch of upper Tepusquet Creek. Slight seepage in bed of creek three-fourths 
of a mile above junction with main stream. At anticlinal axis. Has been located. 

2. On Colson Fork of Tepusquet Creek. Black bituminous streaks, veinlets, and 
pockets, associated with calcareous shales which are considerably folded on a minor 
scale. This also has been located. 

3. Labrea Creek, at and near junction with Rattlesnake Canyon. 

4. Sisquoc dairy. Seepage and asphaltic sands along sharply defined anticline 
which is obscured by later material. Well sunk here, but no record available. 

5. Sisquoc River, one-half mile below Round Corral Canyon. Slight seepage from 
steeply inclined Monterey shale. (Shown in PI. Ill, B, p. 34.) 

6. Fugler Point, 1 mile north of Gary. Veins of asphaltum, parallel in a general 
way to the bedding, which here dips 25° SW., intrude the fossiliferous Fernando 
(lower Pliocene portion). A shaft has been sunk here a few feet for the removal of 
the asphaltum. 

7. Alcatraz mine, 3J miles east of Sisquoc post-office. Vast deposits of asphaltum, 
from a few feet to 200 feet or more in thickness, lie unconforinably above the steeply 
dipping Monterey shales over large areas in the general region of the mine. These 
deposits have been mined on a large scale at one place, but at present the plant is 
idle. The mine is shown in PI. VIII, A. 

8. Zaca Canyon, 5 miles southeast of Sisquoc post-office. Deposits similar to those 
at the Alcatraz mine are found on both sides of La Zaca Creek where it debouches 
from its narrow mountain canyon into the broad valley carved by it through the 
hilly country. 

9. Sisquoc Ridge, If miles north of Sisquoc post-office. A small but significant 
area similar in occurrence to the two preceding. This area overlies the axis of an 
anticline in the Monterey shale. 



U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. VIII 


A. ALCATRAZ ASPHALT MINE, 3 MILES EAST OF SISQUOC. 

Showing the horizontal Fernando brea deposits overlying the steeply tilted Monterey shale. 



B. UNCONFORMITY BETWEEN TILTED MONTEREY SHALE AND HORIZONTAL PLEISTOCENE 

SAND AND GRAVEL. 


In railroad cut northeast of Casmalia. Photograph by Ralph Arnold. 















STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 79 


CONCLUSIONS REGARDING FUTURE DEVELOPMENT. 


On account of the greater intensity of the folding and the lack of 
the thick, more or less unaltered diatomaceous deposits which are 
found associated with all the proved productive fields in this dis¬ 
trict, the indications are not so encouraging for good wells in the 
territory northeast of the head of the Santa Maria Valley as they are 
in certain other portions of the Lompoc and Guadalupe quadrangles. 
The areas in the region of the San Rafael Mountains which offer the 
most inducements for testing by the drill are as follows: 

1. North and northwest of Sisquoc post-office, along the anticlines 
shown on the map (PI. I, in pocket). There are one or two local 
anticlines not shown, which might also be prospected with good 
results. The hard shales exposed in this region are probably lower 
Monterey and, if such, do not offer as much promise of great accu¬ 
mulations of oil at their base as if they were overlain by the upper 
part of the formation. The strata in the region above the head¬ 
waters of Round Corral Canyon and Asphaltum Creek are too sharply 
folded to give much hope of the retention of large deposits of petro¬ 
leum. The asphaltum deposits here and to the southeast indicate 
that the Miocene was at one time highly petroliferous, but that at 
least a considerable portion of the oil has escaped. 

2. In the Monterey area bordering the head of the Santa Maria 
Valley on the northeast, both west and east of Tepusquet Creek, 
wherever the anticlines are not so sharply folded as to give indica¬ 
tions of probable loss of their petroleum content by excessive frac¬ 
turing. The surface evidence of petroleum in this general Monterey 
area is greatest in the southeastern or more sharply folded portion, 
but for obvious reasons it seems likely that the chances for the 
accumulation of economically important deposits of petroleum are 
greatest in the less compressed area northwest of Labrea Creek. 

3. The region about Fugler Point and thence southward and 
southeastward toward Sisquoc. This territory is doubtless under¬ 
lain by the oil-bearing beds, but at what depth it is not possible to 
calculate owing to the fact that the Monterey and Fernando are cov¬ 
ered by later sediments. The occurrence of asphaltum at Fugler 
Point is analogous to that at the east end of Graciosa Ridge, near 
which very productive territory has been developed. The local dip 
at the point (25° SW.) would indicate that the best places to drill 
would be east of the asphaltum deposit; but the uncertainty whether 
this dip is anything more than a local tilting of the Fernando is so 
great that conclusions regarding the best localities for exploitation 
in this immediate vicinity are extremely hazardous. Southwest of 
Fugler Point, however, there is evidence of the presence of a low 


80 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

anticline which should yield good returns if penetrated deep enough. 
This anticline is mentioned further in connection with the Canada 
del Gato a area (pp. 88-89). 

REGION OF SANTA YNEZ MOUNTAINS. 

AREA SOUTH OF LOMPOC. 

South of the Lompoc Valley, the Monterey dips in general north¬ 
ward away from the higher portion of the hills, but south of the 
town of Lompoc is an area of much disturbance, and many folds 
have been developed on the flank of what may be thus broadly con¬ 
sidered as a monocline. These folds have been compressed in dif¬ 
ferent directions and there is a puzzling diversity of dip and strike. 
There are so many local folds that it is difficult to connect the more 
important axes, but the general lines of disturbance are continuous 
for the distance mapped. The main folds south of Lompoc are an 
anticline near the valley and a syncline north of the Monterey- 
Vaqueros contact, with a minor anticline and syncline between. 
The attitude of the beds is extremely variable, the dip ranging in 
general between 15° and 60°. On either side of the main anticline 
between Salsipuedes and San Miguelito creeks the hard shales dip 
away at an angle of 20° to 40°. West of San Miguelito Creek the 
folds swing out toward the valley dr die out on the flank of the mono¬ 
cline, which thus becomes unbroken. 

The greater part of the strata in the hills south of Lompoc belong 
low in the Monterey formation, although higher portions remain in 
the synclinal folds. The disturbance has been considerable, and 
erosion has removed the highest parts of the formation, so that the 
chances have been good for the escape of any oil that may have 
been present. There are no surface indications of petroleum and 
the conclusion is that no great quantity of oil would be found on 
drilling. 

AREA OF SANTA RITA HILLS. 

East of Lompoc the lines of structure cross the Santa Ynez Valley 
into the Santa Rita Hills. These hills are formed of a single main 
ridge which is paralleled on the south side by an important anticline. 
The dips on either side of the broad summit of this fold range from 
a few degrees to about 35°. The general trend of the fold is east and 
west, in conformity with that of the Santa Ynez Range, but it is 
curved, especially at the east end, as if influenced by more than one 
set of forces. Other important folds occur on the flanks of the anti¬ 
cline, giving origin to the disturbed zone followed by Santa Ynez 
River. 


a Called locally Cat Canyon. 





. • 



































































































































































































U. S. GEOLOGICAL SURVEV. 


BULLETIN NO. 322 PL. IX 




A, It. MONOCLINE IN MONTEtlEY SHALE IN CASMALIA HILLS. 

About u miles northwest of Casmalia, looking northwest. Photograph by Ralph Arnold. 



C, D. GRACIOSA AND WESTERN UNION OIL COMPANIES' WELLS. 

South side of Santa Maria field; Mount Solom.on in distance. Photograph by Ralph Arnold. 

























STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 81 

The conditions along this anticline, especially through the eastern 
half of its length, favor the occurrence of some oil at least, as the 
axis exposes beds fairly high in the formation and the folding is 
gentle. No surface indications of petroleum were found, except a 
patch of burnt shale south of the road about 1 mile southwest of the 
highest hill (elevation 1,300 feet) and local outcrops of bituminous 
black flint and brown shale on the west side of the 800-foot hill about 
hall a mile north of the river and 1 \ miles west of the east edge of the 
Santa Rosa grant. 

MAIN PORTION OF THE SANTA YNEZ RANGE. 

The Santa Ynez Range is composed chiefly of Tejon and Yaqueros 
rocks and its structure is therefore much less important in connec¬ 
tion with the oil deposits than that of the areas underlain by the 
Monterey shale. It is dominated by a great southward-dipping 
monocline that forms a high ridge along the coast, north of which the 
strata are gently folded along curving lines that reflect two different 
structural trends. The folds that expose the Tejon-Yaqueros and 
the underlying Franciscan beneath the Monterey toward the west 
end of the range are in places abrupt and complex. The anticline 
of the Santa Rita Hills has the appearance of crossing the Santa 
Ynez Yalley and continuing in a large fold to the southeast. 

REGION BETWEEN THE SAN RAFAEL AND SANTA YNEZ MOUNTAINS. 

CASMALIA HILLS AND SAN ANTONIO TERRACE. 

Two dominant structural lines control the region of the Casmalia 
Hills and the San Antonio terrace. One is a typical fault starting 
on the coast south of Lions Head and the long area of igneous rocks 
and running southeastward. About 2 miles west of Casmalia the 
lin e is continued by an anticline, which is probably affected b}^ faults 
at least as far as Schumann Canyon. This anticline plunges more 
and more toward the southeast and loses its character as a fold, giv¬ 
ing place to the eastward-dipping monocline of the San Antonio 
terrace. 

The other structure line is one of varying character, represented 
on the map as the Schumann anticline. Northeast of the area of 
igneous rocks that meets the - sea at Lions Head Miocene strata 
form a great monocline, dipping rather steeply to the northeast. In 
the high region of Mount Lospe and northeast of the long strike 
ridges (shown in PI. IX, A, B) that extend southeastward from that 
peak, this monocline flattens out into a structural platform of very 
low dip, which on approaching the edge of the steep descent to the 
Santa Maria Yalley bends over and drops off abruptly. The axis 
along which this steepening of the dip occurs is in a way equivalent 


82 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 


to an anticlinal axis and is the line mapped. In places it is a true 
anticline, completed by beds of gentle dip that form a broad syn¬ 
cline of the platform on its southwest side. South of Corralillos 
Creek the structure curves westward and the Schumann anticline is 
sharply defined and overturned. It is seemingly to be correlated 
with a large anticline exposed in the Tejon-Vaqueros rocks on the 
coast north of Point Sal. South of Waldorf this anticline, as shown 
by the dotted line on the map, is not certainly continuous, but west 
and south of Schumann the same or a similar fold becomes well 
developed and the strata dip away from it on both sides. In this 
portion and southeast of Schumann Canyon its summit is broad, 
but the dips become very steep farther out on its northeastern 
flank. It plunges to the southeast and finally dies out. 

Asphalt and other surface indications of oil, such as burnt shale 
and bituminous shale, occur at many places in the Casmalia Hills. 
The shale is especially bituminous along and near its contact 
with the Fernando on the northeastern side of that part of the hills 
which lies north of Schumann, and it has been burnt in a number of 
places in the same region. Outcrops of burnt shale are prominent 
on the hill just southeast of Schumann, and near the contact at the 
northern base of this hill the shale is extremely bituminous. Wells 
put down in the region about Schumann encounter heavy tar at 
depths below 2,000 feet, but no paying wells have been struck. It 
seems likely, however, that at greater depths, possibly 3,000 feet or 
so, the horizon of the productive flinty beds encountered in the 
Graciosa Ridge wells will be penetrated and will yield lighter oil in 
paying quantities. 

The region lying north of Schumann Canyon, west of the valley 
that runs southward out of the hills and opens to Schumann Canyon 
1 mile N. 45° W. of the Casmalia depot, and west of the road that 
crosses the ridge to Waldorf will probably not yield any large quan¬ 
tity of petroleum, because the strata are so low in the formation 
and because there appear to be no sufficiently well-developed folds 
to afford good points of accumulation. Oil might be found in small 
quantities in the minor folds between the lower portion of Schumann 
Canyon and the fault. The shale along the coast here is very bitu¬ 
minous. East and south of the supposedly unproductive region 
outlined above the plunging structure exposes higher portions of the 
Monterey shale and the conditions warrant the conclusion that oil 
can probably be obtained in the neighborhood of the major anti¬ 
cline. Southeast of the point where the road south of Waldorf 
crosses the ridge the territory appears promising, especially along 
the anticline and on its east side. The oil which is supposed to rise 
on the steep eastern flank of the fold probably does not reach far 
under the broad western flank. South of Schumann, where the fold 


STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 83 

becomes more nearly normal, both flanks will probably be found 
productive if penetrated deep enough. The surface structure indi¬ 
cates that the oil horizon plunges to a greater and greater depth 
under the whole region southeast of Casmalia Creek. The anticline 
south of Antonio is well defined and conditions favor the presence 
of oil on both this and the other anticline of the San Antonio terrace. 

The main anticline on the coast north of Point Sal, already men¬ 
tioned, is in the Yaqueros and is doubtless barren of oil. North of 
this locality the Monterey is decidedly bituminous, but no special 
circumstances point to the existence of petroleum in large quantity. 
It is quite possible that the region north of Mussel Pock, the next 
point to the north, would prove promising if the surface covering 
allowed the examination of the underlying formations and the deter¬ 
mination of anticlines. The structure seems to cause the forma¬ 
tions to plunge toward the north from the north end of the Casmalia 
Hills, and a fairly high portion of the Monterey may underlie the 
region at the mouth of the Santa Maria Valley. 

BURTON MESA. 

The plateau known as Burton Mesa is a region of numerous low 
folds in the Monterey. Along the coast the flinty shales are of low 
dip, but folded and contorted in a complex way. The folds indi¬ 
cated on the map are the most important ones, but whether or not 
they are perfectly continuous units across the mesa can not be defi¬ 
nitely ascertained on account of the covering of sand over the shale. 
The mesa appears to be structurally a continuation of the region 
near Lompoc as much as it is of the Purisima Hills, although topo¬ 
graphically it is a continuation of the latter. In the neighborhood 
of Pine and Santa Lucia canyons there is a thick series of shales 
striking far to the north of west and directing the structural lines 
across the Lompoc Valley as if to join those in that region that 
show a tendency to curve northward. West of Pine Canyon the 
strike changes. The Pine Canyon anticline shows this curving 
structure. It is a well-defined fold with broad summits and sup¬ 
ports on its flanks a considerable thickness of shale. The dip ranges 
from 10° to 30°. A characteristic appearance of the shale and dip 
on the northeastern flank is shown in PI. IV, B (p. 36). North of 
this fold occur a number of minor flexures and there is some doubt 
as to the continuity of the anticline mapped at the head of Oak 
Canyon with the well-defined fold near the coast in the vicinity of 
Canada Tortuga. A well-marked low anticline occurs near the coast 
north of Lompoc Landing and probably continues inland. It is 
probable that either one anticline of considerable importance or sev¬ 
eral small component flexures start across the mesa between Tangair 
and San Antonio Creek. The summit of all these anticlines so far 


84 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 

mentioned on Burton Mesa exposes hard shale that is low down in 
the Monterey, and it is probable that with the removal of all of the 
higher portion opportunity has been offered for the escape of the 
greater part of the oil from the basal beds. 

A low anticlinal fold occurs in the northeast corner of Burton Mesa 
and plunges toward the southeast. As indicated by the dotted line 
on the map, it is possibly a continuation of the anticline south of 
Antonio before mentioned and another on the east edge of the mesa 
that is discussed in connection with the Purisima Hills. The evi¬ 
dence of folds in this northeastern portion of the mesa is scanty, but 
it is probable that where they occur accumulations of oil are present. 

The brittle calcareous and flinty shale of the lower portion of the 
Monterey that is exposed along the coast edge of Burton Mesa is very 
bituminous. The petroleum slowly oozes out in some places and 
collects in tarry patches over the shale. Up Oak Canyon the shale is 
bituminous, pockets of tar being found in places in the flint on the 
surface. On the northern border of the mesa, near the point where 
the road to Lompoc comes up the grade, a 3-inch bed of bituminous 
sand was found traversing the shale fairly high in the formation. 

PURISIMA HILLS. 

FOLDS. 

The Purisima Hills are formed by one broad anticline which has its 
axis on the south side of the summit of the dominating ridge. Through 
the major portion of this anticline’s course, from the region north of 
the Hill wells to a point beyond Bedrock Mountain, the beds lie 
almost horizontal on its summit, becoming gradually steeper up to 
an angle of 15° or 20°, or locally even 40°, within a mile or two from 
the axis. The general trend of this fold is more to the north of west 
than that of the Los Alamos or Santa Ynez valleys, but portions of 
it have a more westerly course, as at the west end, where it also 
becomes a steeper fold. At the east end it has the dominant 
northwest-southeast trend characteristic of this part of the hills and 
likewise becomes steeper. It is a fold plunging from either end 
toward the region at the head of Cebada Canyon, where the axis 
of the depression in the anticline occurs. This depression appears 
like a broad syncline crossing the anticline at right angles, with the 
deepest portion of its trough at this point. 

The Purisima Hills anticline can not be traced farther westward 
than is shown on the map, but at the west end there seems to occur a 
structural offset to the northwest, a poorly exposed anticline about 
a mile from the end of the main fold being traceable for a short dis¬ 
tance and seeming to mark the continuation of the general structure 
of these hills. There is a likelihood that oil may be found along this 
fold as well as along the main anticline. 


STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 85 

FAULTS AND ASPHALT DEPOSITS. 

A thrust fault is well exposed in two forks of Cebada Canyon, where 
the Monterey has been thrust to the southwest up over the Fernando. 
The dip of the fault plane is toward the northeast at an angle of about 
30°. The movement has amounted to a few hundred feet. The 
fault zone seems to continue for a considerable distance toward the 
northwest and to be marked near the Wise & Denigan oil well No. 8 
by large asphalt deposits occupying fractures in the Fernando that 
dip at an angle corresponding to that of the fault plane. The asphalt 
back of the Wise & Denigan well No. 1 is probably due to oil that 
has seeped through the same fractured zone and collected in the 
sandy capping. 

The structure of these hills is further complicated by a prominent 
overturned anticline in the Monterey along the contact with the 
Fernando southwest of Los Alamos and by what appears to be a fault 
exposed near the mouth of Canada Laguna Seca. In this fault the 
Fernando limestone and sand are thrown down several hundred 
feet on the north, at the edge of the Los Alamos Valley. 

In addition to the deposits above noted, asphalt occurs in great 
abundance south and east of Redrock Mountain, surrounded by 
a large area of ver}^ bituminous shale and burnt shale. Undoubtedly 
an immense amount, of petroleum has escaped here, but it is not 
probable that the supply is exhausted. On the contrary, the pres¬ 
ence of this petroliferous material on the surface, coupled with the 
favorable structural conditions, points strongly to the existence of 
rich oil deposits beneath. 

A large mass of asphalt is present in the much-fractured Monterey 
shale west of La Zaca Creek, and very bituminous shale approach¬ 
ing asphalt in character occurs on the creek south of Zaca station. 
The shale is bituminous throughout the zone of disturbance traversed 
by this creek south of Zaca. On account of the low position of the 
strata in the formation and the severe fracturing and folding that 
have taken place, it seems probable that the conditions have been 
favorable in this eastern portion of the Purisima Hills for the escape 
of much of the petroleum. 

Small beds of bituminous sands interbedded with soft shale occur 
in the upper portion of the Monterey just east of Canada de la Puenta, 
about three-fourths of a mile south of the Los Alamos Valley; also 
on the north side of the Purisima Hills ridge, about 2 miles south 
of Harris. A small patch of shale that is saturated with bituminous 
material is exposed in the canyon followed by the road 1 mile south 
of the Los Alamos Oil and Development Company well No. 1, and 
the shale is bituminous in the neighborhood of the Todos Santos well. 


86 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


CONCLUSIONS REGARDING FUTURE DEVELOPMENT. 

The Purisima Hills anticlinal fold seems to offer a favorable loca¬ 
tion for oil wells along most of its soutli flank. Owing to the plung¬ 
ing of the fold toward its middle, lower and lower strata are reached 
as its extremities are approached. In the region mapped as Fer¬ 
nando, between the Hill wells and the head of Canada Laguna Seca, 
the summit beds of the Monterey are overlain by later sand and a 
well would have to be drilled to a great depth before reaching the 
oil horizon. East and west of that region the oil horizon probably 
approaches nearer to the surface. In the vicinity of Redrock Moun¬ 
tain, especially to the west of it, the conditions seem very favorable 
for the occurrence of oil. Farther east, near La Zaca Creek, a much 
lower portion of the Monterey is exposed and the rocks have been 
affected by considerable disturbance, so that it is less likely that large 
accumulations of oil will be found there. 

AREA AROUND SANTA YNEZ. 

The Santa Ynez anticline is a distinct steep fold exposed southeast 
of the town of that name. It supports on its flanks a thickness of 
at least 2,500 feet of calcareous and porcelaneous shales belonging to 
the lower portion of the Monterey. The dips at the axis range 
between 50° and 80°, but become lower toward either side. This 
fold is seemingly a structural continuation of that of the Purisima 
Hills, and it probably extends under the gravels of the region around 
Santa Ynez, its axis passing approximately under that town. But 
it is doubtful whether it is actually the same as either of the anti¬ 
clines that are shown on the map as stopping indefinitely near the 
east end of the Purisima Hills. The terraced stretch between La 
Zaca Creek and Ballard seems from the fragmentary evidence obtain¬ 
able to be in a way an undulating structural plateau formed of beds 
low in the oil-bearing shale, dipping at slight angles in various direc¬ 
tions. It is probable that the structure of the Purisima Hills is 
here interrupted, but continued in a general way beyond by the 
Santa Ynez anticline. Owing to the low position of the beds in the 
formation, the chances for finding a considerable amount of oil along 
this anticline do not seem to be as good as farther west. No sur¬ 
face evidence of petroleum was seen. Any definite statements, 
however, in regard to the region between Los Olivos and Santa 
Ynez River and between La Zaca Creek and the east edge of the area 
mapped are hazardous, for the reason that the widespread terrace 
deposits obscure practically all of the structure. 


STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 87 

SOLOMON HILLS AND AREA NORTH OF LOS OLIVOS. 

GENERAL FEATURES. 

Three anticlines dominate the structure of the Solomon Hills. 
These are, in order from west to east, the Mount Solomon anti¬ 
cline (first worked out and named by W. W. Orcutt), the Gato Ridge 
anticline, and the La Zaca Creek-Lisque Creek anticline. In addi¬ 
tion to these there are at least three or four minor anticlines associ¬ 
ated with the first named, and at least one north of that on Gato 
Ridge. 

MOUNT SOLOMON AND ASSOCIATED ANTICLINES. 

Structure .—The details of the northwest end of the Mount Solo¬ 
mon and associated anticlines are shown on the contour map (PI. X, 
p. 92). Whether or not the anticline extending through the Santa 
Maria Oil and Gas and the Escolle properties should he considered 
the true extension of the Mount Solomon anticline, or whether the 
Hartnell anticline should be so considered, is impossible to decide 
with the data at present available. It is the writers’ opinion that 
the Mount Solomon and Hartnell anticlines are the result of the same 
set of forces and should therefore be considered as one fold, but that 
the evidence offered by the data used in compiling the map favored 
the relations shown on PI. X. The mapping of the Pinal, Hobbs, and 
Newlove anticlines is based almost entirely on evidence furnished 
by the drill, although certain superficial evidence strengthens the 
theory of their presence. 

The southeastern portion of the Mount Solomon anticline gradu¬ 
ally fades out into the southern flank of the Gato Ridge anticline, 
losing its individuality toward the southeast end of the Mount Solo¬ 
mon ridge. The northeastern flank of the anticline is much the 
steeper, dipping from 20° to 38° in the region of Mount Solomon, 
and gradually flattening out from that locality southeastward. 

The Western Union anticline is a well-developed flexure with 
steep northern flank just south of the eastern group of Western 
Union wells, but its identity becomes more and more obscure as it 
fades into the southwestern flank of the Gato Ridge anticline in a 
similar manner to the Mount Solomon anticline, just south of the 
latter’s southeast end. 

The relations existing between the Mount Solomon and Schu¬ 
mann anticlines are vague, although it is certain that they are not 
in alignment and therefore can not possibly be one continuous feature. 
If the Hartnell and Mount Solomon anticlines are considered as one, 
the relations which exist between this united anticline and the Schu¬ 
mann anticline are exactly analogous to those which exist between 
the Mount Solomon and Gato Ridge and the Gato Ridge and La 


88 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 


Zaca Creek-Lisque Creek anticlines, viz, the adjacent anticlines are 
en echelon with each other, each plunging down past the end of its 
neighbor. Graciosa and Harris canyons, particularly the former, 
are the superficial reflection of the syncline between the ends of the 
Mount Solomon and Schumann anticlines, and Solomon Canyon and 
Canada de los Alisos occupy analogous positions between the Mount 
Solomon and Gato Ridge and the Gato Ridge and La Zaca Creek- 
Lisque Creek anticlines, respectively. 

Asphaltum deposits .—Practically the whole top of Graciosa Ridge 
is capped by post-Monterey sandstones and conglomerates, which 
are heavily charged with asphaltum. Asphaltum also occurs as 
veins penetrating the Monterey and post-Monterey beds at the 
east end of the ridge, and a fine example of asphaltum veins and vein- 
lets filling the joint cracks in the Monterey is to be seen beside the 
road leading up to the- Santa Maria Oil and Gas (Squires) well No. 4. 
This occurrence of the asphaltum in the joint cracks of the shale 
gives a clew to the probable channels through which the oil migrated 
from the depths to the surface, and leads to the general conclusion 
that joint cracks are the reservoirs and channels of migration of the 
oil in many of the productive strata of this field. 

Conclusions regarding future development .—It is obvious from a 
glance at the contour map (PI. X, p. 92) and a perusal of the detailed 
description of the developed areas that practically all of the terri¬ 
tory covered by contour lines is productive. The only part of the 
region about which the compiler of the map has any misgivings as to 
productiveness is that occupying a general synclinal position south 
of the great bend in the Mount Solomon anticline. These misgivings 
are partially alleviated, however, by the idea that probably the 
position of the territory in question on the flanks of Graciosa Ridge, 
which is, broadly, a quaquaversal fold or dome, may exert enough 
control on the oil to cause its collection there at least in paying 
quantities, if not in the remarkable measure found in other parts of 
this field. The region adjacent to the southeast end of the axis of 
the Mount Solomon anticline ought to be productive. The beds on 
the northeastern flank dip more steeply than those on the south¬ 
western, and the first productive stratum is thought to be at a lower 
horizon in the shale on the former flank than on the latter, so that it 
is probable that the oil zone will be struck at a greater depth from 
the surface northeast of the anticline than southwest of it. 

GATO RIDGE ANTICLINE. 

Structure .—The Gato Ridge anticline extends from the top of the 
ridge just east of the mouth of Solomon Canyon to a point some¬ 
where near the middle of the triangle formed by Canada de los 
Alisos, Cuaslui Creek, and Foxen Canyon. It follows very closely 


STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 89 

the crest of the ridge between Canada del Gato and Solomon Canyon 
and for a considerable distance to the east is coincident with the 
highest topographic features. In general, the anticline plunges from 
the southeast toward the northwest, the lowest beds along its axis 
being exposed in the region of Canada Arena. The Fernando is the 
only formation exposed along the entire length of the anticline. 
\\ ith the exception of some diatomaceous beds which closely resemble 
and were at first mistaken for Monterey shale, the rocks exposed are 
sandstone and conglomerate. 

The northwestern portion of the fold, from the Howard Canyon 
road northwestward, is a gentle arch with dips on the flanks rarely 
more than 5°, except northwest of Los Alamos, where the dips of 
some of the youngest beds exposed change abruptly from 3° or 4° to 
15°. The northwestern extremity of the anticline fades off into the 
low slopes toward the Santa Maria Valley. From Howard Canyon 
eastward the southerly dip increases rapidly in steepness until in the 
region of Canada de los Coches it attains a slope of 25° to 35°, the 
steepest dip being at the junction of the canyon last named and 
Canada Arena. Although the southerly dip increases in steepness 
toward the east along the anticline, the dip of the northern slope 
becomes less, ranging from 12° or 15° in the region of Howard Can¬ 
yon to 3° or 4° just west of Canada Arena, and finally changing to a 
gentle southward slope in the region of Cuaslui Creek, thus fading 
into the southern flank of one of the folds emanating from the region 
at the head of Round Corral Canyon and Asphaltum Creek. In the 
region of Cuaslui Creek the flexure is therefore not a typical anti¬ 
cline in the regularly accepted sense, the horizontal being used as 
datum, but in every other way it conforms to the characters of such 
a structural feature. 

On the ridge north of the central portion of Canada del Gato and 
extending indefinitely northwestward out into the Santa Maria Val¬ 
ley a mile or so southwest of Gary is a low anticline, the southeastern 
end of which merges into the almost horizontal northern flank of the 
Gato Ridge anticline. At no place along its course is this structural 
feature well developed, although it appears to be fairly persistent 
for a considerable distance. 

Evidences of petroleum .—Very little surface evidence of the exist¬ 
ence of petroleum in the Gato Ridge anticline is to be had along its 
course. Near its axis in Cuaslui Creek and north of the head of 
Howard Canyon, however, the Fernando shale is slightly bitumi¬ 
nous. The Pezzoni well, in Canada Arena; the Williams well, near 
Canada del Gato, 1J miles west of the Howard Canyon road, and the 
Palmer Oil Company’s well No. 1, 1 mile west of the lower part of 
Canada del Gato, all approximately a mile north of the anticline, 
offer indisputable evidence of the presence of the oil-bearing rocks 


90 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

along a considerable extent of its northern flank. In the region of 
the Pezzoni well an unproductive oil and gas bed is encountered at 
about 1,200 feet below the surface, immediately followed by a dia¬ 
base or lava rock in which the ferromagnesian minerals have been 
weathered to serpentine. In the Williams well the same or a similar 
oil and gas bed occurs much lower. The well was abandoned owing 
to the terrific gas pressure, which heaved heavy tar up into the hole 
and stopped operations. The Palmer well is productive, yielding oil 
of 16° or 17° gravity. Although not directly associated with the 
minor anticline northeast of Canada del Gato, the asphaltum occur¬ 
ring at Fugler Point, 1 mile north of Gary, is important in indicating 
the probable presence of petroleum in the upper end of the Santa 
Maria Valley. 

Conclusions regarding future development .—The region north of the 
Gato Ridge anticline, from the vicinity of Cuaslui Creek westward to 
a point at least a mile beyond the Howard Canyon road, is underlain 
by strata so nearly horizontal as to preclude their containing very 
productive accumulations of petroleum. North and northwest of 
this region, however, especially near the axes of the Gato Ridge 
anticline and the anticline north of it, the indications are good for 
productive wells. The conditions for the accumulation of petro¬ 
leum are also good along and just south of the axis of the Gato Ridge 
anticline in the vicinity of Cuaslui Creek and from this locality west¬ 
ward to the upper portion of Canada de los Coclies. The same might 
be said of the immediate vicinity of the row of prominent knobs 
which extend in a straight line northwestward for 5 miles from a 
point about a mile north of Los Alamos, and possibly also, but in a 
less degree, for the territory between these knobs and the axis of the 
anticline. These knobs mark an abrupt change in the dip of the 
beds from 3° to 12° SW. to 35° or 40° or possibly more, in the same 
direction. Wells would have to be sunk to a considerable depth 
along this last-mentioned line to reach the oil horizons, but if oil was 
encountered at all it would probably be in such quantities as to pay 
for the deep holes. 

LA ZACA CREEK-LISQUE CREEK ANTICLINE. 

Structure .—The La Zaca Creek-Lisque Creek anticline extends from 
the ridge southeast of Canada del Comasa southeastward at least as 
far as the edge of the Lompoc quadrangle east of Santa Agueda 
Creek. Its course is practically straight except at the northwestern 
extremity, which bows around toward the southwest and is en echelon 
with the east end of the Gato Ridge anticline. The dips along the 
axis are low in both directions, but distant from it they are much 
steeper, being as high as 30° or more to the northeast on the second 


STRUCTURE AND CONDITIONS AFFECTING PRESENCE OF OIL. 91 


ridge east of Figueroa Creek, as shown in PL VI, A (p. 46), and 30° 
SW. at the junction of Figueroa and Lisque creeks. 

Conclusions regarding future development .—No indications of petro¬ 
leum were noticed in proximity to this anticline, and it is almost cer¬ 
tain that no productive wells will be developed on that part of it 
which lies within the Lompoc quadrangle, with the possible excep¬ 
tion of a small area at its west end. There are good reasons for 
believing that the oil-bearing beds are absent from most of its north¬ 
ern flank, and if present under certain portions of its southern flank 
they lie at such a depth as to preclude their successful exploitation. 

SUMMARY OF CONCLUSIONS REGARDING FUTURE DEVELOP¬ 
MENT. 

There can be no doubt that the region treated in this report is one 
of great promise. The structural and other conditions in general 
favor not only much more extensive development of the territory 
that has already been tested, but also the development of new fields. 
It must be borne in mind continually, however, that absolute deter¬ 
mination, by work on the surface, of the possibilities of occurrence 
or nonoccurrence of oil in any one locality is not possible. The 
best that can be done is to calculate the degree of probability on 
the basis of a summation of surface indications and structural con¬ 
ditions. 

The following is a list of the tracts that appear especially to invite 
testing with the drill. Most of them have been discussed in the 
foregoing pages: 

North and northeast of Sisquoc post-office, along anticlines. 

General region east and west of Tepusquet Creek. 

Indefinite area west of Gary, about Fugler Point. 

Santa Rita Hills anticline. 

Near the coast north of Schumann Canyon. 

Schumann anticline in southeastern part of Casmalia Hills. 

Two anticlines on San Antonio terrace. 

Questionable region at mouth of Santa Maria Valley. 

Northeastern portion of Burton Mesa. 

Purisima Hills anticline, more especially the south side. 

Anticline at head of Santa Lucia Canyon. 

Region about Mount Solomon and related anticlines. 

Along Gato Ridge anticline and south of it between Canada de los Alisos and Canada 
de los Coches. 

Row of knobs extending 5 miles northwestward from a point about 1 mile north of 
Los Alamos and the territory between these knobs and the Gato Ridge anticline. 

Region northwest of the head of Howard Canyon, especially along the axis of the 
anticline south of Gary. 

Arroyo Grande field. (See pp. 107-108.) 


92 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


DETAILS OF TIIE DEVELOPED TERRITORY. 

DEFINITION OF FIELDS. 

In the following paragraphs are discussed the more important 
details regarding the structure, geology, oil zones, oil, and production 
in the areas in which development is well under way. These areas 
within the Lompoc and Guadalupe quadrangles fall naturally into 
two fields—the Santa Maria field and the Lompoc field. The former 
covers the whole territorv between the Los Alamos and Santa Maria 
valleys, and the latter is used to designate the region south of the Los 
Alamos Valley. A third, the Arroyo Grande field, covering the ter¬ 
ritory north and northwest of the town of that name in San Luis 
Obispo County, lies to the north of the region mapped, but is briefly 
discussed. A note on the Huasna field, east of Arroyo Grande, is 
also appended. 

SANTA MARIA FIELD. 

CONTOUR MAP. 

WHAT IT SHOWS. 

The contour map of the Santa Maria field (PI. X) shows the bound¬ 
aries of the different properties, the approximate location of all the 
wells, and the general structure of the field. The structure is indi¬ 
cated by contours showing the distance below sea level of a hypo¬ 
thetical horizon, zone, or bed, which just reaches sea level at the 
highest part of the axis of the Mount Solomon anticline. The con¬ 
tour interval is 100 feet. By means of this map the direction and 
amount of dip of the strata in the oil-bearing Monterey shale may be 
calculated for any point in the field, as the contour lines show the 
direction of strike (to which the dip is at right angles), and the hori¬ 
zontal distance between any two contours is the distance through 
which the beds dip 100 feet at that particular point. 

BASIS OF. CONTOUR MAP 

The property lines were sketched from a map kindly furnished by 
Frank M. Anderson. The wells were located in the field bv the eve, 
supplemented by pacing and in some instances by information fur¬ 
nished by the managers of properties. The log of every well in the 
area either finished or down any considerable distance in August, 
1906, was used in the determination of the structure and the com¬ 
pilation of the data concerning the oil zones. All additional informa¬ 
tion available up to January 15, 1907, has been used in a revision of 
the contouring. All of the obtainable surface evidence of dip and 
strike of the beds was also used in the preparation of the map. In 
every case where the surface and well-log evidence were at variance 





Compiled by Ralph Arnold 


SKETCH CONTOUR MAP OF SANTA MARIA OIL FIELD. 










































































































































































DETAILS OF THE DEVELOPED TERRITORY. 


93 


the latter was followed. In the Fernando formation, which uncon- 
formably overlies the Monterey shale, it was natural to expect vari¬ 
ance with the structure in the Monterey, but even here the surface 
evidence more often supported than contradicted the evidence 
obtained by the drill. 

DIFFICULTIES OF PREPARATION. 

After carefully plotting all the logs on a uniform scale it was found 
that the greatest obstacle to overcome in the preparation of the con¬ 
tour map was the correlation of strata from one well to another and 
from one part of the field to another. The difficulties of such corre¬ 
lations are doubtless familiar to anyone who has tried to work out 
the underground structure of any of the California fields. The Santa 
Maria field offers as much encouragement to successful study and 
mapping of the underlying oil-bearing formations as any other so far 
examined by the senior author, and so the effort has been made to 
delineate on the map all the details of structure furnished by the 
data available, and to supplement these details by showing for the 
untested areas what seem to be the most likely conditions of under¬ 
ground structure. It is very easy to make an ambiguous statement 
which will apply equally well to any conditions exposed by future 
development, no matter what they may be; but it is impossible to 
make an ambiguous map. However, it is deemed advisable to show 
the information in hand, incomplete as it is, on a map. Future 
development will doubtless add much to our knowledge of this field, 
and will show the inaccuracies of the contouring as here presented, 
but it is hoped that the benefits which may accrue to the operators 
from a knowledge of the general structure of the field will compen¬ 
sate in a measure for the errors in detail which are to be expected in 
a map based on data so incomplete. 

THE WELLS. 

AREAS DISCUSSED. 

For convenience of discussion the proved portion of the Santa 
Maria field has been roughly divided into six areas, based largely 
on the geographic position of the wells. The following are the areas 
discussed: Hall-Hobbs-Pice ranch; Pinal-Fox-FIobbs; Pinal-Fol- 
som-Santa Maria Oil and Gas-Escolle; Hartnell-Brookshire; Gra- 
ciosa-Western Union; and eastern Western Union. 

OIL ZONES. 

Although in many instances detailed correlation from one well 
to another is impossible, four fairly well defined oil zones are believed 
to be recognizable in the Santa Maria field. Of these at least two 
are found in practically every part of the field, although all vary 
1784— Bull. 322—07-7 



94 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


more or less in thickness, composition, and yield from well to well. 
The most persistent zone in that part of the field which is best 
developed at the present time is the second, or B zone. Above 
this in many of the wells is zone A; in others zone C is penetrated 
below it. The upper zone in the eastern group of Western Union 
wells, although above what is supposed to be the horizon of B, is 
probably considerably above the A zone of the northern part of the 
field, where it appears to have no correlative. 

With the exception of the lowest zone in the wells in the eastern 
part of the field and of a few others mentioned in the detailed dis¬ 
cussion of the local areas, the oil zones appear to represent fractured 
portions of the shales, the interstices in the breccia or possibly joint 
cracks in the beds being the reservoirs for the storage of the oil. 
The exceptions to the brecciated productive zones are apparently 
typical sands and gravels. 

HALL-HOBBS RICE RANCH AREA 

LOCATION AND STRUCTURE. 

The area here discussed comprises the California Coast, Meridian, 
Coblentz, Santa Maria Oil Company (Keyser), Hall & Hall, New 
Pennsylvania, Rice ranch, and Dome properties and the north¬ 
eastern part of the Hobbs lease, and occupies the ridges and canyons 
which extend northward from the east end of the main Graciosa 
Ridge. The wells are located on the northwestern flank of the 
Mount Solomon anticline, at or immediately northwest of the ter¬ 
ritory, in which it swings from a northeastward to a southeastward 
trend. In addition to the main anticline there appear to be one or 
more local flexures involved in the structure of the field, the Hobbs 
anticline and the syncline between it and the Mount Solomon anticline 
being the most prominent. The characteristics and extent of these 
features as they are believed to exist are portrayed on the contour 
map (PI. X). 

GEOLOGY OF THE WELLS. 

• • 

Nearly all the wells in this area, with the exception of the Hall, 
Meridian, and Coblentz start down in the Monterey shale. Those 
farthest away from the top of the ridge, other things being equal, 
have to penetrate farthest through the Fernando clay, sand, and 
conglomerate. Up to the present time the greatest thickness of the 
Fernando penetrated before reaching the shale is 650 feet, and much 
trouble was experienced in going through it in this well, the forma¬ 
tion being mostly sand. From the top of the Monterey shale to the 
bottom of the wells the rocks are largely blue and brown shales, 
with only here and there interbedded hard “shell” layers. In fact, 


DETAILS OF THE DEVELOPED TERRITORY. 


95 


one log reports “no shell” until the first oil zone is reached. Wher¬ 
ever ‘‘shell” is penetrated accumulations of gas or oil or both are 
generally encountered. The shale seems to be somewhat more sandy 
in this area than farther west' or in the Graciosa-Western Union 
region. 

Three oil zones are recognizable in the area under discussion, 
although practically all the strata from the top of the uppermost 
zone to the bottom of the lowest are more or less petroliferous at 
one point or another. 

The first productive zone (A) is penetrated at a depth of 1,600 
to 2,100 feet, varying according to the position of the well geograph¬ 
ically and relatively to the axis of the anticline. Its top is from 550 
to 700 feet above the top of zone B in this area. Zone A is produc¬ 
tive for a distance in the wells of 20 to more than 500 feet. Of course 
this does not mean that the beds are productive in any one well for 
the whole distance of 500 feet, but that throughout the zone alternat¬ 
ing barren and productive beds occur at such close and as a rule 
irregular intervals as to preclude their practical differentiation. The 
productive measures in this first zone consist both of hard frac¬ 
tured shale or “shell” and more or less porous sandy layers. In at 
least one of the wells the oil accumulates only under the hard “shell” 
layers. Zone A is the only one penetrated by some of the wells 
farthest away from the anticlinical axis. In these wells it appears 
to be much more petroliferous than in wells higher up on the fold. 

The second oil zone (B) is from 550 to 700 feet below the top of 
zone A, and its upper limit is about 300 or 400 feet above the top of 
zone C, although it can hardly be said to be distinct from C in all 
the wells, so rich in oil are some of the intervening strata between 
them. True sands of medium grain, in addition to the productive 
hard shale, yield the oil in this zone. 

The third oil zone (C) is encountered in some of the deeper wells 
nearest the axis of the main anticline. This zone has been pene¬ 
trated for as much as 150 feet, the whole distance being very rich 
in petroleum. It is overlain by a considerable thickness of black 
shale, also more or less petroliferous, between which and the rich 
zone is a thin, hard “shell” layer. The oil-yielding rock is a true 
sand, coarse in places and even becoming pebbly toward its base in 
certain portions of the area. To the coarseness of the material is 
doubtless due the great productiveness of the zone. 


PRODUCT. 


The oil in the Hall-Hobbs-Rice ranch area runs from 26° to 29° 
Baume and is dark brown in eojor. Gas accompanies the oil and also 
occurs isolated under some of the more impervious “shell” layers 
in the shale. No water is reported in any of the wells. 


96 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


The production of the wells ranges from 300 to something over 
2,000 barrels per day. Those wells which penetrate the lowest or C 
zone are the best producers. It is said that where a number of wells 
are located comparatively near together the production of each well is 
largely dependent on whether or not the adjacent wells are producing, 
a fluctuation of 50 per cent resulting from this cause in some instances. 

PINAL-FOX HOBBS AREA. 

LOCATION AND STRUCTURE. 

The area comprising the Fox lease, the southwestern part of the 
Hobbs lease, and the northeastern portion of the Pinal property, 
occupies the ridge and two adjacent canyons which extend north¬ 
ward from the central portion of Graciosa Ridge. The wells are 
located in an area of considerable structural disturbance caused by 
the development of two local anticlines on the northwestern flank of 
the main Mount Solomon anticline. These two minor flexures have 
been named after the companies under whose property they are best 
developed. Although the position assigned to them on the map is 
more or less hypothetical, the evidence in favor of it is fairly complete, 
and their location explains some of the variations in production of 
adjacent wells. 

GEOLOGY OF THE WELLS. 

Practically all the wells within this area start in the Monterey 
shale, and this is the prevailing formation to their bottoms. Certain 
portions of the shale are burnt to a brick-red color by the combustion 
of their hydrocarbon contents, the burnt shale being encountered as 
low as 330 feet in one of the wells. The burning has so hardened the 
shale in places as to render drilling in them more difficult. A hard 
limestone “ shell ” layer was encountered in one of the wells just above 
the second (B) oil zone. Tar or asphaltum occurs in some of the wells 
at a depth of about 600 feet, in others at various depths from 200 to 
1,200 feet. The tar is in many wells associated with black shale. 
Gas accumulations under “shell” and other impervious layers are of 
common occurrence both in the oil zones and locally in the barren 
overlying shale. Water is encountered in some of the wells at 
depths ranging from 150 to 270 feet. This occurrence is noteworthy, 
as the wells in the group to the east are, so far as known, quite free 
from water in the shale. Its occurrence in the Fernando sands and 
conglomerates is to be expected, but its presence in sands inter- 
bedded with the shale is unusual for this field. 

The first oil zone (A) is penetrated in the wells in this area at 
depths ranging from a little more than 1,600 to 2,650 feet, or between 
400 and 600 feet above zone B. (See PI. X, p. 92.) Petroliferous 
strata occur in some of the wells above this horizon, but they are of 


DETAILS OF THE DEVELOPED TERRITORY. 


97 


little consequence as regards production. The thickness of zone A 
in the wells ranges from 8 or 10 to nearly 150 feet, but several more 
or less important oil-bearing zones lie between this and the next 
lower (B) zone. The productive measures of zone A consist largely 
of brown shale, probably seamed or jointed in such a way as to afford 
a reservoir for the oil, although certain of the wells may obtain their 
product from fine-grained sands int erst ratified with the shale. 

The second oil zone (B) is the most important one in this area, 
although it is underlain over at least a part of the area by zone C, which 
is apparently even more productive. The thickness of zone B is 
variable, but most of the wells penetrate from 50 to 150 feet of pro¬ 
ductive strata at this horizon. The oil-bearing beds are similar to 
those of zone A and appear to consist largely of hard shales, with 
some fine sands, although some excellent examples of a true siliceous 
sand are obtained in many of the wells. A hard limestone “shell” 
overlies zone B in one well. 

The third oil zone (C) is penetrated by some of the deeper wells 
at a depth of about 300 to 400 feet below zone B. In one of the 
wells zone C appears to be missing, although a good flow of oil is 
reported from the same hole about 500 feet below where it should 
occur. 

Water underlies oil-zone B in one of the wells and zone C in another. 
This occurrence of water below the oil, so common in most fields, 
is very rare in this one. Whether or not in the course of time water 
will follow up the oil in the productive zones is something that will 
be awaited with a great deal of interest. Some of the wells in the 
Santa Maria field have been stopped in the midst of productive strata 
for fear of encountering water farther down, but whether or not 
these fears were well founded has never been established. 

PRODUCT. 

The oil from this group of wells is of a dark-brown color and 
ranges in gravity from 24° to 28° Bauine, the lighter oil usually occur¬ 
ring in the wells nearest the main anticline; the average gravity is 
between 25° and 26°. Much gas is associated with the oil in all the 
wells. 

The production of the individual wells ranges from 60 to 1,000 
barrels per day, the latter amount coming from a hole very eccentric 
in its behavior, as shown by its yield of 200 barrels on some days 
and as high as 1,000 on others; the average daily production for this 
well is 300 barrels. With the eccentric well omitted, the maximum 
production is about 500 barrels per day. One well which produced 
150 barrels from zones A and B added 350 barrels to its output when 
deepened to zone C. 


98 


SANTA MARIA OTL DISTRICT, CALIFORNIA. 
PINAL-FOLSOM-SANTA MARIA OIL AND GAS-ESCOLLE AREAS. 

LOCATION AND STRUCTURE. 

The area discussed in this section comprises the Folsom lease, the 
southern part of the Pinal property, the central and southern portion 
of the Santa Maria Oil and Gas lease, and the Escolle property of 
the Union Oil Company. The wells are located on the west end of 
Graciosa Ridge and in the canyons on its sides. The region is largely 
covered by the Fernando sandstone and conglomerate ‘‘cap rock,” 
although the Monterey shale is exposed in the side canyons. The 
structure underlying this part of the field is comparatively simple 
so far as known, the main Mount Solomon anticline, which plunges 
northwestward through its center, being the only fold of consequence 
immediately affecting the area. The mapping of the anticline near 
Escolle well No. 3 is based entirely on the evidence offered by the 
well logs, which is at variance with the northwesterly dips in the 
Fernando in the vicinity of Escolle wells Nos. 2 and 3. 

GEOLOGY OF THE WELLS. 

Those wells which start in the Fernando remain in this formation 
for distances ranging from a few feet to nearly 300 feet, the strata 
penetrated being sand and conglomerate. In the region of Escolle 
well No. 1 and Folsom well No. 1 the Fernando appears to be excep¬ 
tionally deep, extending nearly 300 feet below the surface, and to 
consist largely of conglomerate. One of the wells reports red con¬ 
glomerate at 30 to 90 feet below the surface; whether this is burnt 
shale so hardened as to come out of the well in fragments of consid¬ 
erable size or whether it is true water-worn material is not known. 
Asphaltum is reported at the base of the Fernando in some of the 
wells, and may also be seen at the contact between the Monterey 
shale and overlying beds at many places in this area. (See PI. 
XI, A.) The channels through which this material has escaped 
from the shale are undoubtedly joint cracks, as veins of the hardened 
asphaltum may be seen in the shale beside the road leading up to 
Santa Maria Oil and Gas (Squires) well No. 4 and at other points in 
the field. From the base of the Fernando to the bottom of the wells 
the strata penetrated are practically all shale with a few hard “shell” 
layers, under which occur accumulations of gas and locally of oil. 

A zone in which “shells” appear to be particularly abundant 
immediately overlies the first oil zone. Traces of tar and asphaltum 
are also reported in the shale at various depths. Two zones in 
which many hard limestone “shells” layers are encountered are 
reported from some of the wells; one of these is about 500 feet above 
the second oil zone (B), and the other immediately underlies it. 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XI 



.4. DARK-COLORED FOSSILIFEROUS BREA DEPOSIT OVERLYING MONTEREY SHALE. 

Graciosa Ridge at Folsom well No. 3; Pinal camp on left and Santa Maria Valley in distance. Looking 

north. Photograph by Ralph Arnold. 



B. SADDLE IN MONTEREY, FERNANDO, AND PLEISTOCENE BEDS. 

Graciosa Ridge at Hartnell well No. 1, near Orcutt; Pleistocene on left, Fernando (Pliocene) in 
upper right, Monterey (Miocene) in saddle. Looking east. Photograph by Ralph Arnold. 


















DETAILS OF THE DEVELOPED TERRITORY. 


99 


The first oil zone (A), which lies from 250 to 500 feet above zone B, 
is struck at depths ranging from 1,400 to 2,450 feet. Its thickness 
ranges from a few feet to about 50 feet; according to the logs it is 
lacking in some of the wells, the first oil being encountered in zone B. 
The oil-bearing strata in zone A are largely shale, which afford a 
reservoir for the oil, probably on account of their fractured condition. 
Beds of fine sand in this zone may also contain some of the petroleum. 

The second oil zone (B), occurs at depths of 1,950 to 3,150 feet 
and is penetrated by all of the wells in this area. It ranges in thick¬ 
ness from nearly 50 to about 250 feet, in the wells; one of the wells, 
however, is- said to encounter petroliferous beds intermittently from 
the top of zone B for a distance of 550 feet downward. The oil¬ 
bearing strata consist of alternating layers of hard shale and fine 
sandstone. 

The third oil zone (C), occurs from 500 to 600 feet lower in the 
wells than zone B and consists of two parts, each from 25 to 50 feet 
thick, separated by a layer of shale of variable thickness; in one of 
the wells, however, the intervening shale is missing and the strata 
are richly impregnated with oil from the top of the zone for a distance 
of 250 feet downward, to a point where a 3-foot layer of water sand 
limits the productive zone. In practically all the wells in the field 
zone C is very rich, and nearly all the wells tapping it are fine pro¬ 
ducers. 

PRODUCT. 

The oil obtained in the area under discussion averages somewhat 
better than that in the area to the east, and has a gravity of 26° to 28° 
Baume, with an average somewhere between 26° and 27°. As is com¬ 
mon in other portions of the field, the gas pressure in most of the 
wells is high. 

The production of the individual wells ranges from 100 to 2,700 
barrels per day, the well yielding the latter amount being said to have 
had an initial daily output of 5,000 barrels for a short time. In one 
series of wells those down the dip are more productive than those 
nearer the axis of the anticline, the variation being at least partially 
accounted for by a thickening of the oil zone away from the axis. 

HARTNELL BROOKSHIRE AREA. 

LOCATION AND STRUCTURE. 

The area comprising the southern portion of the Hartnell tract 
and Brookshire property and the southeastern portion of the Radium 
lease is located on or adjacent to the ridge running northwestward 
from a point near the west end of Graciosa Ridge, and in the broad 
valley to the south. The major structural feature developed in the 


100 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


beds underlying the area is a northwestward-plunging anticline which 
is here called the “Hartnell. ” There is both surface and underground 
evidence of its presence, hut its exact location is, of course, only con¬ 
jectural. As will be noticed on examining the map (FI. X, p. 92) 
the northern flank of the anticline is much steeper than the south¬ 
western, this fact apparently having a direct hearing on the produc¬ 
tiveness of the wells penetrating this flank. 

GEOLOGY OF THE WELLS. 

The surface distribution of the formations in the immediate vicinity 
of the little swale on the ridge in which Brookshire wells Nos. 3 and 4 
are situated is very interesting. The bottom of the swale is Monterey 
(Miocene) shale; unconformably overlying this on the south is fossil- 
iferous Fernando (Pliocene) sandstone and conglomerate; immedi¬ 
ately north of the swale is terrace-deposit (Pleistocene) sandstone. 
(See PI. XI, B.) It has been suggested that such a condition is most 
easily explained by the presence of a fault through the swale, the 
downthrow being on the north. The logs of the wells in the immediate 
vicinity, however, offer evidence that such is not the case, but that 
the underlying Monterey strata, followed almost immediately north 
of the swale by fossiliferous Fernando beds, plunge steeply north¬ 
ward and are overlain unconformably by the low-dipping or prac¬ 
tically horizontal terrace beds which are exposed on the ridge north 
of the swale. Some of the wells starting in the post-Monterey forma¬ 
tions penetrate sand and gravel for a distance of more than 600 feet 
before entering the Monterey. Limestone, probably corresponding 
layers associated with fossiliferous beds at the base of the 
Fernando in the railroad cut north of Schumann, is reported as occur¬ 
ring next to the Monterey shale in one of the wells. Water is encoun¬ 
tered in gravel at various horizons in the Fernando between the depths 
of 150 and 600 feet. Hartnell well No. 3 and Brookshire well No. 1 
(the latter about half a mile northeast of the area under discussion), 
which penetrate the water-bearing Fernando, are used as water wells. 
From the base of the Fernando to their bottoms the wells penetrate 
blue and brown shale, and very rarely fine sandy layers. “Shell’’ 
strata, many of them underlain by gas and some by oil and gas, are 
encountered here and there throughout the shale. 

The first oil zone (A) occurs about 400 feet above zone B, is struck 
at depths ranging from 2,150 to more than 3,000 feet, and is said to 
be from 2 to 5 feet thick. On examination of the material coming; 
from this and the underlying productive zones, it is quite apparent 
that the oil must come from the joint cracks or interstices between 
the fragments of more or less fractured shale, as no true sands of suffi¬ 
cient coarseness to allow the rapid transmission of the oil have been 
encountered in the productive zones in the wells of this group. 


to the limy 


DETAILS OF THE DEVELOPED TERRITORY. 


101 


Between the first zone and the one that has been recognized as the 
second, or zone B, are one or more productive zones 2 to 15 feet thick. 
No two wells show the same sequence of these zones and they prob¬ 
ably represent places of local fracturing. 

The second oil zone (B) is thought to be fairly constant through¬ 
out the area. It consists of alternating barren and productive layers 
of shale, some of the productive layers being from a few feet to as 
much as 20 feet thick. Below the main or upper part of this zone 
are other productive layers, some at least 200 feet below zone B. 
The oil-bearing measures in these zones, as in zone A, are probably 
nothing more or less than fractured portions of the shale. 

PRODUCT. 

The oil from the wells in this area runs from 24° to 26° Baume, and 
is dark brown in • color with the exception of that from one of the 
wells, which is said to be a reddish emulsion of oil and water. All 
the wells show much gas, the best producers, especially, being under 
heavy pressure. 

The production of the individual wells in this group ranges from 
an initial output of 12,000 barrels per day in one well to a daily aver¬ 
age of 150 barrels in another. The following statement concerning 
the production of Hartnell well No. 1, the greatest producer in the 
California oil fields, has been kindly furnished by Mr. Orcutt, of the 
Union Oil Company: 

4 

Well (Hartnell No. 1) started to flow over derrick through 81-inch and between this 
and 10-inch casing December 3, 1904. Gas pressure was very heavy, estimated at 400 
pounds per square inch—was probably much higher, however. Oil was measured in 
an open ditch by use of a miner’s-incli measuring box, and showed 31 miner’s inches, 
or about 12,000 barrels per day. The flow continued for about sixty days and gradu¬ 
ally weakened. September 1, 1905, the well was doing 3,069 barrels per day. 

The oil was stored in earthen reservoirs, and the production to the above date is esti¬ 
mated at 1,500,000 barrels from this well alone. Up to August 15, 1906, the total pro¬ 
duction for the well was something over 2,000,000 barrels. 

The gas accompanying the initial flow of oil was estimated at 4,000,000 cubic feet 
per day. After the well had been gotten under control it furnished gas for running 
20 boilers for well-drilling rigs, and in addition supplied the town of Orcutt (popula¬ 
tion about 200) with gas for domestic purposes. At the present time it is still yielding 
a constant flow, which is used for many purposes in Orcutt. 

GRACIOSA-WESTERN UNION AREA. 

LOCATION AND STRUCTURE. 

The wells at the northeast corner of the Graciosa and northwestern 
corner of the Western Union properties are located on the point of 
the rid ire which runs southward for more than a mile from the main 
Graciosa ridge. The structure of the beds underlying the devel¬ 
oped area is apparently simple, as they are on the southwestern 
flank of the hypothetical Newlove anticline. At least two minor 


102 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

folds occur on this flank, one apparently passing through Western 
Union wells Nos. 21 and 22 and the other occurring from three-eighths 
to five-eighths of a mile farther northwest. The Newlove anticline as 
shown on the map is wholly hypothetical. It is the expression of the 
most plausible explanation of the relationship which is supposed 
to exist between the known Graciosa-Western Union and the eastern 
Western Union well areas. The surface evidence of the structure 
consists of a 10° SE. dip in the Fernando beds just north of the 
Graciosa wells, together with some more or less uncertain dips in the 
Monterey toward the head of the ridge, approximately parallel with 
which the anticline is supposed to run. 

GEOLOGY OF THE WELLS. 

The wells all start in the sands of the Fernando, penetrating this 
formation for 70 to 300 feet. No water is reported from this sand, 
but asphaltum is said to have been found at its base in one of the 
wells. From the base of the Fernando to the top of the main pro¬ 
ductive zone the formation consists of blue and brown shales with 
many hard “shell” layers, some beds of sticky shale, and rarely a 
little sandy material. Streaks of asphaltum are reported as occur¬ 
ring in the shale in some of the wells, and in others gas is present 
under some of the “shells.” 

The first oil zone (B of the^ northern part of the field) is reported 
from only one well, where it is nearly 200 feet thick and is encountered 
at a depth of about 2,075 feet. Gas is associated with the oil in this 
zone. 

The second and important oil zone of this area (C) is struck at 
depths ranging from 2,670 to something more than 3,800 feet, and 
lies about 600 feet lower in the wells than zone B, which is apparently 
unproductive in most of the wells. According to the data in hand, 
the productive zone ranges in thickness from 18 to about 240 feet 
and consists of alternating light and dark flinty shales interbedded 
with varying amounts of sandy shale. No true sand, as ordinarily 
implied by the name, occurs in the productive zone of this area, so 
far as the writers were able to learn. 

PRODUCT. 

The oil from zone C runs from 25° to 27° Baume, averaging well 
up between 26° and 27°, and has a brownish color. It comes from 
the wells at a temperature of about 95° F. and is usually accompanied 
by much gas. Certain of the wells, however, are said to show a 
comparatively low gas pressure. 

The production of the individual wells ranges from 300 to 3,000 
barrels per day, the flow of many being unusually strong. None of 
the wells have been allowed to produce up to their full capacity, 


DETAILS OF THE DEVELOPED TERRITORY. 


103 


owing to the lack of storage and transportation facilities, so that 
even had they been down long enough for a thorough test (which 
is hardly the case, inasmuch as nearly all have been finished since 
1904) no definite conclusions could be drawn concerning their lasting 
properties. 

EASTERN GROUP OF WESTERN UNION WELLS. 

LOCATION AND STRUCTURE. 

The eastern wells of the Western Union Company are located near 
the head of one of the branches of the broad valley which extends east- 
northeastward from Harris Canyon, at Blake, and are about 5 miles 
southeast of Orcutt. They are from one-half to three-fourths of a mile 
east of the west property line of the company and close to the north 
line. Slightly more than half a mile to the northeast of the wells is 
the axis of the Mount Solomon anticline, from the southwestern flank 
of which the wells derive their oil. The structure in the immediate 
vicinity of the wells, as indicated by the logs (see PI. X, p. 92), is more 
or less complicated, the general strike of the beds apparently changing 
abruptly from northwest to southwest immediately northwest of the 
group. Furthermore, a local flexure with northeast-southwest strike 
immediately underlies the developed territory, and a pronounced 
anticline (here named the “Western Union’) with a steep northeast¬ 
ern flank lies just to the south. There is no surface evidence of the 
northeast-southwest disturbance, but the Western Union anticline 
is plainly to be seen in the Fernando beds. The dip of the beds on the 
southwestern flank of this fold ranges at the surface from 15° at the 
west end of the hill south of the wells to 10°, and possibly much less, 
one-half mile to the southeast. The maximum northeasterly dip of 
45° occurs south of well No. 18, but the slope rapidly decreases both to 
the northwest and southeast. As nearly as could be ascertained from 
the available data, the production of the wells in this group supports 
the anticlinal theory of the accumulation of petroleum—that is, for 
an equal thickness of productive zone the wells near the axis of the 
anticline in the local flexure are more productive than those farther 
away from it. 

GEOLOGY OF THE WELLS. 

The wells start in soil, but soon enter the clay, sand, and conglom¬ 
erate layers of the Fernando, which is the surface formation in this 
part of the field. The Fernando beds are penetrated for 100 to 250 
feet, varying with the location of the well, the wells on the north, as 
would be expected after an examination of the surface geology, pass¬ 
ing through it in the shortest distance. Water and quicksand were 
encountered in at least two of the wells in the lower portion of the 
Fernando; in another, asphalturn occurs at the base of the formation. 
From the base of the Fernando to the first oil zone the wells penetrate 


104 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 

blue and brown shales, largely the latter, interstratified with hard 
“shell” layers, under some of which are accumulations of gas. 

The first oil zone is struck at a depth of 1,200 to 1,800 feet, and 
ranges in thickness from 12 to 75 feet, although in some of the wells 
sands are encountered at intervals for at least 250 feet below the top 
of the first sand. The oil sand is as a rule rather fine grained and is 
accompanied both above and below by shale and rarely by shell. In 
some of the wells the oil zone appears to be practically continuous 
sand for its entire thickness; in others, alternating sand and shale 
layers furnish the oil. 

A second oil zone occurs about 1,200 feet below the first, the entire 
distance between the two being occupied by shale, with a few hard 
“shell” layers. Very little oil occurs at this horizon. 

A third oil zone about 150 feet thick is penetrated 2,100-feet below 
the first, the formation between the second and third zones being prac¬ 
tically all shale. Comparatively little oil was obtained from this zone 
in this part of the field, although it is thought to be the same as the 
one which is so productive in the Graciosa Western Union area only 
half a mile to the west. This may be accounted for by the general 
synclinal position of the eastern group between the Mount Solomon 
and hypothetical Newlove anticlines. 

PRODUCT. 

The oil in the first productive zone has an average gravity of about 
19° Baume and is very dark colored. Gas is associated with the oil, 
but no water has so far been reported from any of the wells. 

The production of the wells in this group ranges from 5 to 154 bar¬ 
rels per day. The yield of some of the wells is fairly constant, show¬ 
ing only a small decrease in average daily output over a considerable 
number of months; in others, however, the yield is fluctuating. 

LOMPOC FIELD. 

LOCATION. 

The developed territory within the Lompoc field, on which the fol¬ 
lowing discussion is based, lies on the flanks of the Purisima Hills be¬ 
tween the Cebada Canyon and Santa Lucia Canyon roads. Within it 
are located the Logan well of the Los Alamos Oil and Development 
Company; the Hill, Wise & Denigan, and Eefson wells of the Union 
Oil Company; and the abandoned wells of the Todos Santos, Coast 
Line, and Barca oil companies. 

STRUCTURE. 

The dominant structural feature of the field is the main anticline 
of the Purisima Hills. From surface evidence the location of the 


DETAILS OF THE DEVELOPED TERRITORY. 


105 


anticline is believed to be that shown on the map (PI. I, in pocket); 
from the evidence offered by the logs of the Hill and Logan wells the 
axis of the anticline, so far as it affects the oil-bearing beds of this part 
of the field, might better be drawn through Hill well No. 1, extending 
westward and eastward (swinging to the north in both directions) to 
the points where the “ surface” anticline passes from the Fernando 
to the Monterey. In either location, however, the anticline has a 
steeply dipping northern flank and a low-dipping and probably undu¬ 
lating southern flank. 

A fault, clearly seen on the east side of Cebada Canyon and traced 
by deposits of asphaltum over portions of the rest of its course, 
extends from a point a short distance east of Cebada Canyon north¬ 
westward at least as far as the brea deposits near Wise & Denigan 
well No. 1. This is clearly a reverse fault in the Cebada Canyon 
region, supposed Monterey diatomaceous shale being thrust up on the 
north over Fernando sandstone which lies south of the line, the dip 
of the fault plane being about 30° toward the north. Mr. Orcutt 
suggests that this fault probably causes the difference in yield be¬ 
tween Hill wells Nos. 2 and 3. The sand is struck about 700 feet 
lower in No. 3 than in No. 2, and is barren in the former but produc¬ 
tive in the latter. The dip in the strata (if the anticline affecting 
the oil sands passes south of well No. 2) might account for the differ¬ 
ence in depth of the oil sand in the two wells, but it alone would 
hardly account for the difference in saturation of the sands. It is 
quite possible that the fault (which theoretically emerges somewhere 
near Hill well No. 4) passes downward at such an angle as to cut the 
oil sand between Hill wells Nos. 2 and 3, throws the sand down on the 
north, and, while acting as an outlet for the oil in the sand for some 
distance on its northern or upper side, effectively seals up the trun¬ 
cated end of the same sand on its southern or lower side. This 
hypothesis assumes a downthrow on the north, a condition exactly 
opposite to that shown at the surface in Cebada Canyon. Alternate 
upthrow and downthrow on the same side of a single fault occurring 
at different times are not unusual in the Coast Ranges, so that such 
an explanation is not only possible but probable. To conform to the 
prevailing conditions the downthrow must have been on the north 
in pre-Fernando and on the south in Fernando or post-Fernando 
time. 

The logs of the Wise & Denigan wells indicate a more or less local 
anticline in the Monterey. Its axis passes near well No. 2 of this group, 
and probably extends in an east-west direction parallel to the major 
lines of structure in the hills immediately to the north. This occur¬ 
rence suggests the probable gentle folding of the Monterey in the 
region south of the Purisima Hills, in a manner similar to that which 
takes place under Burton Mesa farther west. 


106 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


GEOLOGY. 

GENERAL STATEMENT. 

All the productive wells in the Lompoc field start in the Fernando 
formation and penetrate its clays, sandstones, and conglomerates 
for distances ranging from 45 to 800 feet. The great variation in the 
thickness of the Fernando in adjacent wells (the beds over much of 
the territory being nearly horizontal, implies great inequalities in the 
surface of the underlying Monterey shale, and this in turn signifies a 
profound unconformity between the two formations. Water is 
encountered in the Fernando at various depths in the different wells. 

From the base of the Fernando to the top of the oil sand the wells 
pass through shale (largely “brown,” according to the logs). Hard 
siliceous “shell ” layers are encountered here and there in this shale, 
and in one well hard limy “shells” were struck at only 1,180 feet 
from, the surface. These limy layers are abundant in the formation 
just above the oil zone, but are not found in most of the wells above 
this horizon. 

Oil and gas are found in minor quantities in the shale at various 
depths, from 500 feet down in some of the wells in the northern part 
of the developed area, although such occurrences are not recorded for 
the wells in the southern part. 

BURNT SHALE. 

One of the most interesting features of the geology of the Monterey 
shale in this area is the evidence that combustion has taken place 
within it at certain points about 1,000 feet below the surface. Mr. 
Orcutt, of the Union Oil Company, exhibited samples of red shale 
coming from depths of 950 and 1,040 feet below the surface in Hill 
well No. 1, which are identical in appearance and texture to the burnt 
shale found so abundantly in the bituminous areas of the Monterey 
on the north side of the Santa Maria field and in other fields through¬ 
out the State. Traces of petroleum were associated with the upper 
stratum of burnt shale in Hill well No. 1. 

OIL ZONES. 

The principal productive oil zone in the Lompoc field is struck at 
depths below the surface ranging from about 2,200 to more than 
4,100 feet. In nearly all the wells-the productive strata are overlain 
by a more or less prominent series of limy “shell ” layers, which appar¬ 
ently act as barriers to the upward migration of the oil at the present 
time. The beds beneath these limy “shells” are true sands in most 
places, although in some of the wells these sands are interstratified 
with varying quantities of shale and limestone “shells.” The thick¬ 
ness of the oil zone varies from about 160 to 700 feet, and a productive 
series of sands, shales, and “shells” is said to be penetrated for a 


DETAILS OF THE DEVELOPED TERRITORY. 107 

distance of 1,100 feet in one well. Either water sand, dry oil sand, or 
limy “shell” usually defines the base of the productive zone. 

THE OIL. 

Two grades of oil are struck in this field, one a black oil with a 
gravity of 18° to 24°, the other a brown to greenish oil of about 35° 
Baume. The black oil is produced by most of the wells, the 
lighter variety coming only from the Logan well of the Los Alamos 
Oil and Development Company and the No. 3 Wise & Denigan well 
of the Union Oil Company. The relations of occurrence of the two 
grades are not known. One of the wells yields an emulsion of water 
and 20° oil, which is reddish brown in color as it comes from the well. 
This oil turns to the usual black color on separation of the water by 
settling. 

PRODUCTION. 

The production of the individual wells ranges from 100 to 1,000 
barrels per day, the best producers averaging from 300 to 500 barrels. 
One of the wells which gave an initial output of 200 to 300 barrels at 
first, suddenly began flowing 1,000 barrels per day. This continued 
for a few days and then gradually fell off to 300 barrels, which it is 
still yielding. It is said that the wells, as a rule, are exceptionally 
steady producers, falling off but little in the two years since the field 
was first opened. A ery few of the wells have been tried to their full 
capacity, so that it is probable that yields greater than those men¬ 
tioned will be recorded when the field is fully tested. 

ARROYO GRANDE FIELD. 

LOCATION. 

Drilling has recently shown that at least certain portions of the 
region north and northwest of Arroyo Grande, in the San Luis quad¬ 
rangle, San Luis Obispo County, a short distance north of the area 
shown on PI. I, are underlain by productive oil formations. The 
successful wells belong to the Tiber Oil Company, and are located on 
the west side of Price Canyon about 3 miles northeast of Pismo and 
7 miles slightly east of south of San Luis Obispo. Although outside 
of the immediate area covered by this report the occurrence is so 
important in showing an extension of the Santa Maria district toward 
the northwest as to merit mention here. 

GEOLOGY. 

The geology of the San Luis quadrangle has been mapped and 
described by II. W. Fairbanks in .the San Luis folio. a According to 

a Copies of this folio, which is No. 101 in the series making up the Geologic Atlas of the United States, 
should be in the hands of every oil man or other person interested in the natural resources of this region; 
it may be obtained for 25 cents from the Director of the United States Geological Survey, Washington, 
D. C. 



108 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

this work nearly all of the territory of the hills between San Luis 
Obispo Creek and the Arroyo Grande Valley, with the exception of 
a rather small area of Monterey volcanic ash, shale, and diatoma- 
ceo.us earth north of Pismo, is covered by the Pismo formation. 
This formation is composed of sandstone, some of which is asphaltic, 
and cherty diatomaceous beds, and is the equivalent of the lower 
part of the Fernando formation as described for the hills adjacent to 
the south side of the Santa Maria Valley. The Pismo is unconform- 
ably underlain by the Monterey shale, which outcrops on either side 
of it. 

STRUCTURE. 

According to Fairbanks, the Pismo area forms a low syncline, 
striking northwest and southeast, its flanks resting against the up¬ 
turned Monterey. 

OCCURRENCE OF THE OIL. 

The oil is derived from a great thickness of productive sands which 
probably represent the base of the Pismo and which rest upon the 
upturned and more or less contorted shale of the Monterey. Its 
occurrence in beds occupying a synclinal position is worthy of note, 
as ordinarily synclines are not highly productive. The Monterey is 
the oil-bearing formation in the Santa Maria district, and it is the 
ultimate source of the oil in this field also. The migration of the oil 
probably took place along joint cracks in the shale, as was the case 
with the asphaltum in the Santa Maria and other fields. The oil, on 
reaching the upper limit of the shale passed across the plane of uncon¬ 
formity and accumulated beneath an impervious shale in the porous 
sands at the base of the Pismo. Where this porous layer approaches 
the surface the more volatile parts of the oil have escaped arid there 
remains nothing but the bitumen, while the more deeply covered 
sands retain the oil in its lighter and liquid state. The migration of 
the oil, as in every similar case coming under the notice of the writers, 
has been accompanied by a loss of its volatile constituents and a con¬ 
sequent lowering of the gravity. This is evidenced by the fact that 
although the gravity of the oil from the Monterey formation in the 
Santa Maria field averages about 25°, that from the Pismo in the 
Arroyo Grande field is only 14°. 

CONCLUSIONS REGARDING FUTURE DEVELOPMENT. 

It seems almost certain that considerable portions of the Pismo 
formation toward the middle of the area northwest and north of 
Arroyo Grande will be found to be oil producing. This conclusion is 
based on the assumption that the Pismo of this region is underlain 


OIL OF THE SANTA MAE IA DISTRICT. 


109 


by the oil-yielding Monterey. The surface evidence of such a condi¬ 
tion is most conclusive. What effect local flexures either in the Mon¬ 
terey below the Pismo or in the Pismo itself will have on the produc¬ 
tion, only drilling will determine. According to Fairbanks’s interpre¬ 
tation of the structure of the area, the depth at which the oil will be 
struck ought to decrease from the middle of the area toward both 
the northeast and southwest. The only well fully tested in the region 
yields 500 barrels of 14° oil per day, so that the prospects for the de¬ 
velopment of a good field are unusually bright. 

As the Monterey shale underlying the Pismo of the Arroyo Grande 
field is continuous with the Monterey mapped in the Lompoc quad¬ 
rangle northeast of the Santa Maria Valley, it is reasonable to suppose 
that there are considerable portions of this great belt of Monterey 
that will prove productive. The local structure is usually the deter¬ 
mining factor in the accumulation of the petroleum, so that a thor¬ 
ough knowledge of this is essential to economical test drilling. 

HUASNA FIELD. 

The Huasna field lies east of the Arroyo Grande field and north of 
the Lompoc quadrangle. Prospect drilling is now going on in this 
region, but with what results the writers are not able to say. During 
a very hasty trip through this region in the summer of 1905 the senior 
writer noted great areas of Monterey shale, with some interbedded 
coarse granitic sandstones, in many places of considerable thick¬ 
ness. Such conditions are ideal for the accumulation of petroleum 
if the beds are not too sharply folded. This Monterey area is prob¬ 
ably the continuation of that exposed in the northeastern part of the 
Lompoc quadrangle, and may connect the latter with the Monterey 
area east of Arroyo Grande and also with that covering the summit 
of the Santa Lucia Range a few miles east of San Luis Obispo. It is 
to be regretted that no maps adequate for showing the structure of 
the formations in the region east of the San Luis quadrangle and 
north of the Lompoc quadrangle are available. Without these it 
will be impossible to do for this region such detailed geologic and 
structural mapping as has already been done for the two quadrangles 
mentioned. 


OIL, OF THE SANTA MARIA DISTRICT. 

ORIGIN. 

There is no doubt that the petroleum in the Santa Maria dis¬ 
trict is indigenous to the Monterey shale. Bitumen is a character¬ 
istic part of that formation throughout its wide extent over an area 
covering hundreds of square miles, and there is no other formation 
1784—Bull. 322—07-8 


110 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 


but the Eocene shales in which it is characteristic, or in which 
it occurs in appreciable quantity except locally, although there are 
numerous formations which would be capable of storing oil if any 
had originated in them. Moreover, the bituminous Monterey shale 
of the Coast Ranges does not occur consistently above or below 
any one formation from which the oil could have been derived. It 
lies unconformably upon ancient metamorphic rocks; granite and 
other igneous rocks; Jurassic, Cretaceous, or early Tertiary sedi¬ 
ments; or conformably over lower Miocene beds, according to local 
conditions; and it is either not covered by later deposits or is buried 
by sediments of various ages, in different places. 

The decision is therefore unavoidable that some ingredients of the 
Monterey shale gave rise to the oil, and the question arises what these 
were. The organic composition of the strata making up this forma¬ 
tion is discussed on pages 38-43, where a number of animal and 
plant forms that may have contributed to the oil are enumerated. 
The writers are strongly of the belief that the petroleum was derived 
largely from the minute organisms, especially the plant organisms 
(diatoms), which are present in such abundance in these shales. The 
chemists Peckham and Clarke believe that the nitrogen present in 
the California oil proves its origin from animal substance. But it is 
not necessary to consider that this petroleum originated entirely 
from either animal or vegetable matter; it is more probably the 
product of remains of both kinds combined, much of the nitrogenous 
material being furnished by animal tissue. 

Other small organisms of a low order present in the Monterey shale 
besides the diatoms are Foraminifera and Radiolaria, both orders of 
marine animals. They became embedded in the mass of the organic 
and adventitious silt material of the deposit at the sea bottom, and 
their bodies were thus preserved with the hard parts and may have 
become a source of hydrocarbons and nitrogen for the petroleum. 
The fact that the limestone and calcareous shale of the Monterey are 
usually very bituminous suggests the conclusion that the Foraminif¬ 
era were great oil formers, inasmuch as these rocks are thought to be 
made up largely of foraminiferal remains, although of course the 
calcareous strata may owe their petroliferous character to their 
porosity. In many places the body o£ the limestone is full of minute 
specks of oil contained in cavities about the size of the interior of 
foraminiferal skeletons, and these specks give the impression that the 
oil is not far from its point of origin. Albert Mann, of the United 
States Department of Agriculture, makes the suggestion that possibly 
Foraminifera originally made up a greater part of the shales than 
now appears and that tlieir easily destroyed calcareous tests were 
leached out, the soft parts adding their quota to the total amount of 
petroleum formed and owing to their animal character helping to 


OIL OF THE SANTA MARIA DISTRICT. 


Ill 


cause the relatively high percentage of nitrogen found in the Califor¬ 
nia oils. 

Fish skeletons are sometimes found in the shale, and flat impres¬ 
sions, large and small, that appear to be the scales of fish are abun¬ 
dant and very characteristic of certain portions of this formation, 
seeming to show that fish remains were in sufficient abundance to 
add at least something to the oil and to supply a portion of the nitro¬ 
gen. On the other hand, these fossilized parts may have been origi¬ 
nally separated from the tissue before they dropped to the ocean 
bottom or before being buried in the deposit, as by far the greater 
number of fish are believed to die violent deaths and to serve as food 
for larger fish or other animals. 

Other animal organisms which were present and which may have 
contributed hydrocarbons and nitrogen were sponges, mollusks, and 
crustaceans—such as crabs and possibly ostracods. The impres¬ 
sions of seaweed occur in the shale but sparingly, probably because 
plants of this kind are restricted in habitat to shallower water than 
that in which it is believed the greater part of the Monterey was laid 
down, so that it is not probable that these plants have been large 
contributors to the material of the oil. 

It is certain that there was a sufficiency of organic material in¬ 
cluded with the Monterey deposits to give rise to a vast quantity of 
petroleum, as is proved by a rough estimate based on low calcula¬ 
tions of the amount of such material present. If the area covered 
by the Monterey formation in the Santa Maria district, including 
territory surely covered by it whether the formation now outcrops 
there or not, be taken as 800 square miles and the thickness of the 
formation as half a mile, the total volume of the deposit would be 
400 cubic miles. These figures are low, especially in view of the fact 
that the average thickness and the areal extent of the formation were 
much greater when the oil began to be accumulated than at present. 
If we regard for the moment the diatoms alone to be the source of 
the oil, and only 1 per cent of the formation to be made up of these 
organisms, there would be 4 cubic miles of diatoms; and if we sup¬ 
pose further, simply as a rough guess, that these forms gave rise to 
an amount of petroleum equaling 1 per cent of their volume, we 
would have 1,000,000,000 barrels of oil as the amount distilled 
within the Monterey in this district, or more than thirty-three times 
the total production of oil in California for 1904, or eight times the 
production in the United States for the same year. According to 
Albert Mann, who has recently made an extensive study of diatoms, 
these plants when living secrete algal wax or oil in amounts varying 
from 0.75 per cent to as much as 4 per cent of their total volume. 
The amount of petroleum that might be derived from the diatoms 
is entirely unknown; but if the figure assumed hypothetically as 


112 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


being 1 per cent is too liberal, it would seem that the low estimates 
of the amount of diatomaceous material present and the complete 
ignoring of the other important organic sources for oil in the shale, 
would still cause the estimate to be conservative. 

In considering the question, What kind of organic material has a 
character most favorable for producing oil ? the relative rate of putre¬ 
faction is important. Plants have the advantage in respect to their 
slower rate of decomposition. David White inclines to the view that 
plants are more favorable to the production of oil, largely for this 
reason. He. says that putrefaction, which is largely a bacterial 
process, goes on more rapidly in animal tissue, while vegetable mate¬ 
rial has a tendency to turn into hydrocarbons. The slow decompo¬ 
sition of the protoplasm contents of the diatom frustule is especially 
significant. F. J. Keeley, of the Philadelphia Academy of Natural 
Sciences, says as follows in a letter: 

The only point I can think of that might have any bearing on the question of the 
relation of diatoms to petroleum is the fact that the organic matter of diatoms does not 
appear to decompose and become dissipated quickly after death, as is the case with 
most low organisms. It is well known that diatoms kept in water will show the 
shrunken contents for years, and Elirenberg noted the presence of such organic con¬ 
tents in old fossil diatoms from Hanover, while J. Brun reports a similar observation 
in a fossil deposit from Holland. 

It is worthy of note that many of the round white diatom tests of 
the soft Monterey shale contain minute specks of black that appear 
like bituminous material derived in situ from the diatom. These 
specks, however, are present in but a small proportion of the tests 
and there is no proof that the black substance has not come from 
infiltration and deposition in the slight hollow of the shell. Thin 
sections of the shale reveal small black filaments that appear to be 
carbonaceous material. 

It is probable that the ooze at the sea bottom in Monterey time 
was being deposited very rapidly. The idea of rapid accumulation 
of the deposits of diatoms, aided by the accession of organic and 
detrital material of other kinds, is quite in keeping with the well- 
known faculty of these organisms for quick and abundant reproduc¬ 
tion; and it is not only in keeping with but an essential corollary of 
the fact that deposits of such vast thickness were formed during 
middle Miocene time. This rapid accumulation created further 
favorable conditions for the production of oil, inasmuch as the organic 
substance that reached the sea floor became quickly buried without 
sufficient time intervening for decomposition to go very far. Thus 
the contents of the diatom frustules and all the other plant and 
animal remains became included in the body of the deposit. 

The alkalinity of the shale may have been another favoring factor. 
As the deposits grew, salts of the sea water were probably included 


OIL OF THE SANTA MARIA DISTRICT. 


113 


ill the porous mass and they may have acted as preservatives of the 
organisms to some extent. 

As regards the age of the oil, it is stated by F. W. Clarke a that the 
process of formation of the oil from organic sources may not be slow, 
but, on the other hand, comparatively rapid. It is usually thought, 
however, that the process of distillation is slow and is continued 
during a long time. The petroleum in the Monterey may have been 
formed immediately after the deposit was laid down, or the pro¬ 
duction of it may be still in progress. There is evidence, however, 
in the presence of burnt shale in a Pleistocene deposit (see p. 52), 
in the old and eroded deposits of asphalt, and in the presence in cer¬ 
tain asphalt deposits of the bones of extinct Pleistocene mammals 6 
which were caught in tar springs in Pleistocene time, that much of 
the oil at least was formed in the Monterey and disseminated to the 
surface a long time ago. The accumulation and dissemination of the 
oil has probably gone on continuously ever since its first formation, 
the two processes taking place simultaneously. There may be por¬ 
tions of the formation from which the livdrocarbon content has not 
yet been extracted in the form of oil, whereas other portions may 
no longer contain any of the oil in its original disseminated condi¬ 
tion. The metamorphism that gave rise to the harder shales may 
have had the effect of driving out the oil more completely than it 
has been separated from the softer shale, and thus aided its accumu¬ 
lation, although this is conjectural. 

The general conclusion is that in the Santa Maria district the 
organic material in the Monterey shale that may have acted as the 
source of the oil was without a doubt adequate in amount for the 
production of the vast quantity of petroleum now present, and that 
the forms included in greatest abundance, the diatoms, were the 
chief source, although animals and perhaps other plants also con¬ 
tributed largely. 

PHYSICAL PROPERTIES. 

GENERAL STATEMENT. 

The Santa Maria district yields four distinct grades of petroleum, in 
addition to the heavy oil which flows from sprjngs or collects as 
asphalt deposits. These petroleums vary widely in their physical 
and chemical properties and as a consequence are utilized in many 
different ways, the lighter oils usually for refining, the heavier for 
fuel, road dressing, etc. 

The oil as it comes from the wells contains varying quantities of 
gas, often amounting to a considerable percentage. The two prod- 

a The data of geochemistry (in preparation for publication by the United States Geological Survey). 
b Bull. U. S. Geol. Survey No. 309, 1907, pp. 154-155. 



114 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 


ucts are usually separated at the wells, the gas being utilized for 
heat or directly for power and the oil being run into tanks. This 
tank oil still contains gas, most of which, however, gradually passes 
off on exposure to the air, with a consequent lowering of the gravity of 
the oil. Before transportation by steamer it is necessary to pass 
the oil through a partial refining process for the removal of the 
lighter, volatile, more dangerous constituents; this is done at present 
in the refineries at Port Harford and Gaviota. 

COLOR AND ODOR. 

Nearly all of the oil in the Santa Maria district is dark brown in 
color. The exceptions are the black oil from the Arroyo Grande 
field, the reddish emulsion from one of the wells in the Hartnell- 
Brookshire area, and the brown to greenish oil found in certain of 
the wells in the Lompoc field. The heavier oil is the darker; the 
lighter grades show the greenish hues. The darkest oil in the Santa 
Maria field proper is the 19° petroleum from the wells in the eastern 
Western Union group. Some very dark oil is also said to come 
from the Lompoc field. 

The heavy oil gives off an aroma not unlike some grades of lubricat¬ 
ing oil, and, doubtless owing to the absence of hydrogen sulphide in 
solution, has little of the disagreeable odor common to that from 
some of the other California districts. In this district the lighter the 
oil, as a rule, the sharper and less agreeable is its odor. 

GRAVITY. 

The gravity of the oil ranges from 14° to about 35° Baume. The 
heaviest oil (14°) comes from the Arroyo Grande field; 18° to 24° oil 
from the Lompoc field; 19° oil from the eastern group of Western 
Union wells; 24° to 29° oil from the Santa Maria field; and 35° oil 
from the Los Alamos Oil and Development Company’s well and one 
of the Wise & Denigan wells. The average gravity of the oil from 
the Santa Maria field proper is between 26° and 27°, thus putting it 
well into the class of valuable refinable petroleums. 

VISCOSITY. 

The relative viscosity of several of the oils from the Santa Maria 
district, together with similar data for other California oils, is shown 
in the table on page 116. 

CHEMICAL PROPERTIES. 

Few data concerning the chemical properties of the oil from the 
Santa Maria district are at present available for publication except 


OIL OF THE SANTA MARIA DISTRICT. 


115 


those found in Bulletins Nos. 31 and 32 of the California State Min¬ 
ing Bureau. The analyses of Santa Maria oil contained in these 
bulletins were made by H. N. Cooper, and, together with those of 
oils from some of the other California districts, are copied in the 
table below. 

The only definite information concerning the ultimate composi¬ 
tion of the oil is contained in a table by P. W. Prutzman a showing 
the incidental constituents of California crude oil. This author 
states that a Santa Maria oil of 17° (probably from the eastern group 
of Western Union wells) contained 0.43 per cent of nitrogen, no sul¬ 
phur, and 8.37 per cent of asphaltene. The freedom of the Santa 
Maria oil from sulphur is one of its chief and valuable characteristics. 

The following table 6 contains analyses of four oils from the Santa 
Maria district, accompanied by analyses of twelve other California 
oils for purposes of comparison. The oil of analysis No. 3 in the 
table is the most characteristic of the average product of the Santa 
Maria field. 

Following the table are distillation tests. 

Chemical analyses of California petroleum. 

[By H. N. Cooper, chemist. Samples collected by Marion Aubury, field assistant.] 


No. of analysis. 

- t - 

Name of company. 

County. 

District. 

Gravity. 

Specific 
gravity 
of crude 
at 15° C. 
(about 
60° F.). 

1 

Western Union Oil Co. 

Santa Barbara ... 

Western Union.. 

° B. 

20 

0.9337 

2 

......do. 

.do. 

Carreaga. 

34.6 

.8508 

3 

Pinal Oil Co. 

.do. 


27.6 

.8882 

4 

Union Oil Co. of California. 

.do. 

Lompoc. 

16.2 

.9574 

5 

Sea Cliff Oil Co. 

.do. 

Summerland. 

14.9 

.9665 

6 

7 

King Refining Co. 

I. W. Shirley. 

Kern. 

Los Angeles. 

Kern River field.. 
Middle field. 

13 

16.5 

.9792 

.9559 

8 

Southern Pacific Oil Co. 

Kern. 

McKittrick... 

18.5 

.9425 

9 

Home Oil Co. 

Los Angeles. 

Whittier. 

20.7 

.9291 

10 

Brea Canyon Oil Co. 

Orange. 

Fullerton. 

23 

.9147 

11 

Los Angeles Pacific Rwy. Co. 

Ventura. 

Santa Paula. 

27.3 

.8900 

12 

Union Oil Co. of California. 

.do. 

Adams Canyon... 

Coalinga. 

.do. 

28.9 

.8814 

13 

14 

California Oilfields (Limited). 

Home Oil Co. 

Fresno. 

.do. 

31.3 

34.1 

.8680 

.8530 

15 

16 

Los Angeles Pacific Rwy. Co. 

Pacific Coast Oil Co. 

Ventura. 

Los Angeles. 

Timber Canyon... 
Tico Canyon. 

35.1 

37.3 

.8481 

.8367 





a Bull. California State Mining Bureau No. 32, 1904, p. 224. 

b For a detailed description of the methods used in obtaining the data recorded in this table the 
reader is referred to Bull. California State Mining Bureau No. 31, p. 1; idem, No. 32, 1904, table opp. 
p. 230; or to Bull. U. S. Geol. Survey No 309, 1907, pp. 20.5-208. 

























































116 SANTA MARIA OIL DISTRICT, CALIFORNIA. 


Chemical analyses of California petroleum —Continued. 


No. of analyis. 

Flash. 

Viscosity- 

Sulphur. 

Calorific 
value of 
dry 

samples.a 

Calorific 

values 

per 

cubic 

centi¬ 

meter. 

At 15° C. (about 60° F.). 

At 85° C. 

(185° F.). 

Seconds. 

Seconds 
divided by 
27^ or water =1. 

Seconds. 

Seconds 
divided 
by 27* or 
water =1. 


O 



• . 


Per cent. 



1 

Below 15 

1,060 

38. 40 

77^ 

2.81 

2.08 

10,369 

9,907 

2 

15 

47f 

1.72 

29§ 

1.07 

.60 

10,825 

9,203 

3 

Below 15 

90 

3.27 

37^ 

1.36 

1.56 

10,543 

9,364 

4 

21 

Over 1,800 

Over 65.00 

227 

8.23 

4.43 

10,258 

9,822 

5 

Above 70 

Over 1,800 

Over 65.00 

108 

3.91 

.44 

10,348 

10,001 

6 

A Iahvp. 70 

Over 1 800 

Over 65 00 

410 

14.86 




7 

Above 70 

Over 1, 800 

Over 65.00 

78 

2.83 

.85 

10,437 

9,976 

8 

32 

1,100 

39. 85 

54 

1.96 

.77 

10, 402 

9,804 

9 

26 

393 

14. 24 

43 

1.56 




10 

» Below 15 

264 

9. 56 

Ri 

- 1.50 

.94 

10,581 

9,678 

11 

Beln\v 15 

613 

2.23 

34* 

1.24 




12 

Below 15 

162* 

5.91 

37 

1.34 

.48 

10,647 

9,384 

13 

Below 15 

56 

2.03 

32J 

1.18 

.38 

10,739 

9,321 

14 

Below 15 

28i 

1.03 

25J 

.99 

.06 

10,598 

9,040 

15 

Below 15 

45* 

1. 66 

314 

1. 13 




16 

Below 15 

O 

38^ 

1.40 

29J 

1.07 

.28 

11,141 

9,322 


. . Distillation. 

OQ 

•H------- 


>. Percentage. 

o3 _ 


o 

6 

fc 

Water. 

Up to 
100° C. 

100°-150° 

C. 

150°-200° 

C. 

200°-250° 

C. 

250°-300 o% 

C. 

300° C. to 
asphalt. 

• 

As¬ 

phalt. 

Loss or 
gain. 

A. 

B. 

1 

None. 

0.9 

6 

10.5 

9.3 

11 

39.5 


22 

-0.8 

2 

None. 

8.6 

16 

12 

13.4 

10.8 

23 

7.4 

8 

- .8 

3 

None. 

8.2 

17.7 

12.1 

9.4 

9.1 

29.7 


12 

-1.8 

4 

7 

1.3 

3.9 

5.5 

7.7 

18.3 

34.3 


20.6 

-1.4 

5 

.7 

0 

0 

1 

10 

17.4 

45.5 


23.5 

-1.9 

6 

None. 

0 

0 

0 

0 

22.5 

37.5 

6.9 

31.1 

-2 

7 

.8 

0 

0 

0 

7.6 

13.9 

40 

14.5 

21.8 

-1.4 

8 

None. 

0 

4.2 

8.9 

8.7 

20.2 

27.5 

7.5 

22.5 

- .5 

9 

None. 

0 

4.2 

9.6 

14 

14.7 

23 

16.8 

15.7 

-2 

10 

None. 

4.2 

13.9 

8.9 

9.7 

18.3 

24.2 

5 

13.3 

-2.5 

11 

None. 

9.3 

16.5 

11.8 

7.7 

9.1 

31.8 


13 

- .8 

12 

None. 

4 

14.1 

9.1 

9.3 

10. 1 

43 


9.8 

■ - .6 

13 

None. 

10.4 

13.8 

10.5 

10.3 

17.5 

20.8 

7.3 

9.1 

- .3 

14 

None. 

5.5 

30.6 

21.5 

25.4 

8. 1 

5 


4. 1 

+ • 2 

15 

None. 

15.3 

15 

9.5 

9.9 

9.9 

28 


10.6 

-1.8 

16 

None. 

10.5 

■20.4 

13.8 

13 

11.1 

16.9 

6.8 

6.8 

- .7 


yi 

’go 

Distillation. 

G 

Gravity of preceding fractions at 15° C. (about 60° F.). 

O 






300° C. to asphalt. 

o 

Up to 100° C. 

d 

O 

O 

1C 

1 

o 

o 

o 

150°-200° C. 

o 

O 

1 

8 

o 

0 

O 

250°-300° C. 



£ 






A. 

B. 

1 


0. 7596 

0.8087 

0.8538 

0.8875 

0.9167 


2 

0.7185 

.7683 

.8028 

.8354 

. 8574 

.8788 

0.8822 

3 

.7123 

. 7617 

.8132 

.8583 

. 8899 

. 9085 


4 


. 7737 

. 7906 

.8316 

.8613 

.8992 


5 




.8516 

. 8840 

.9347 


6 





.8901 

.8997 

8938 

7 




.8625 

.8849 

.9021 

9053 

8 


.7760 

.8235 

.8427 

.8976 

.8982 

.8985 

9 


.7756 

.8313 

.8672 

.8991 

.9210 

.9166 

10 

.7252 

.7701 

.8172 

.8597 

.8937 

.8955 

.9062 

11 

.7228 

. 7724 

.8202 

.8613 

.8901 

.9154 


12 

.7250 

.7736 

.8111 

.8388 

.8547 

.8778 


13 

. 6906 

.7630 

.8041 

.8382 

.8774 

. 8866 

. 9062 

14 

.7395 

.8074 

.8396 

.8919 

.9227 

.9374 


15 

.7002 

.7639 

.8015 

.8321 

. 8624 

.8875 


16 

.7472 

.7659 

.8040 

.8359 

. 8606 

.8870 

.8720 


« To convert calories into British thermal units, multiply by 1.8. 









































































































OIL OF THE SANTA MAEIA DISTRICT. 


117 


Proximate analysis oj a Santa Maria oil. a 

[Gravity, 10.9° Baurne.] 



Per cent. 

Gravity 

(°B.): 

DISTILLATION. 

Below 150° C... . 

1.0 

24.0 

31.1 

41.9 

2.0 

2.7 
16.8 
36.6 
41.9 
2.0 


150° to 270° C.. . 

39.5 

Above 270° C. . 

Asphalt, grade D. 


Loss.. . 


CALCULATED ANALYSIS. 

Total gasoline.•>. 

55 

41 

Kerosene... 

Middlings and lubricants. 

Asphalt, bv volume f> . 


Loss. 





a Prutzman, P. W. t Bull. California State Mining Bureau, No. 32, 1904, Table 25. 
By weight (154 pounds per barrel), 46.2 per cent. 


The following analyses of oils from the Santa Maria district have 
.been kindly furnished by Prof. Edmond O’Neill, of the University of 
California, who writes concerning them as follows: 

1 do not know the exact locations of the wells from which these oils were derived, 
but they are from the first wells opened in the Santa Maria property [probably the 
Hartnell or the Santa Maria Oil and Gas Company lease]. There is very little differ¬ 
ence in the character of oils from all this district, except in the proportion of light 
constituents and the corresponding percentage of sulphur. Most of these oils contain 
water, which seems to be either in a state of fine emulsion, or possibly in some feeble 
form of hydration—that is, frequently the water will not settle out on standing, even 
by centrifugalizing—nor will it all be driven off at a temperature of 100° Centigrade; 
but at a somewhat higher temperature it seems to be.given off almost with explosive 
violence. 

Analyses and tests of six samples of oil from wells near Santa Maria. 

[Made by Edmond O’Neill.] 

ANALYSES. 



No. 3. 

No. 4. 

No. 5. 

Gravity at 15.5° C. (=60° F.). 

Gravity in degrees Baumd. 

Flash point, open tester.. 

Flash point, closed tester. 

Burning point, open tester... 

Gasoline precipitate (asphaltine, etc.).per cent.. 

Sulphur.do- 

Calorific value.calories.. 

Calorific value.B.T. U.. 

0. 891 
27.800 
(«) 

(«) 

23° C.=73.4° F. 
0.6 
1.57 
10,260 
18, 468 

0.894 
27. 600 

(«) 

(a) 

22° C.=71.6° F. 
0.3 
1.59 
10,363 
18, 653 

0.893 
27. 500 

(«) 

(«) 

21° C. =70° F. 
0.8 
1.56 
10,229 
18,415 


No. 6. 

No. 7. 

No. 13. 

Gravity at 15.5° C. (= 60° F.). 

Gravity in degrees Baum6. 

Flash point, open tester. 

Flash point, closed tester. 

Burning point, open tester....-.- - • 

Gasoline precipitate (asphaltine, etc.).per cent.. 

0.897 
' 26.800 

(«) 

(a) 

21° C. =68° F. 
0.7 
1.61 
10,284 
18,512 

0.908 
24.800 
(a) 

[“) 

20° C.=68° F. 
1.6 
2.09 
18,375 
18,676 

0.926 

21.670 

(«) 

(a) 

24° C.=75° F. 
3.0 
1.8 
8,078 
14,541 

Calorific value. 

Calorific value. B.I.U.. 


a Under 15°C.=60° F. 









































































118 SANTA MARIA OIL DISTRICT, CALIFORNIA. 


Analyses and texts of six samples of oil from wells near Santa Maria —Continued./ 


RESULTS OF DISTILLATION. 


Water, percent by volume.. 

Benzines, boiling point un¬ 
der 150° C. (302° F.): 

Percent. 

Kerosene, boiling point 150° 
0.-250° C. (302° F.-482°F.): 

Per cent. 

Lubricants, boiling point 
250° 0.-350° C. (482° F.- 
662° F.): 

Per cent. 

QraTit Hlaum“ c .::::::::: 

Lubricants, boiling point 
above 350° C. (666° F.): 

Percent. 

r<u 1 - (Baum6. 

Asphaltum: 

Percent. 


No. 3. 

* 

No. 4. 

No. 5. 

No. 6. 

No. 7. 

No. 13. 

1.2 . 

0.2 

Trace. 

Trace. 

Trace. 

10.8 

24.5 

.745 

60° 

22.1 
.740 
61. °2 

20.2 
.740 
61. °2 

23.5 

.752 

52° 

18.5 

.752 

52° 

16.8 
.742 
60. °8 

21.5 

.8345 

39 

20.5 

.821 

41.8 

21.5 
.818 

42.5 

18.7 

.823 

41.4 

18.5 

.822 

41.4 

22.1 

.843 

37 

19.0 

.905 

25.3 

22.8 

.889 

28.2 

19.2 

.898 

26.6 

20.0 

.897 

26.6 

25.5 

.895 

27 

17.2 

.899 

26.4 

23.0 

.917 

23.2 

22.7 

.905 

25.3 

20.3 

.924 

22 

25.5 

.917 

23.2 

22.5 
.903 

25.6 

16.2 

.906 

25 

10.8 

11.7 

8.8 

12.3 

15.0 

16.9 


ASSOCIATED HYDROCARBONS. 

NATURAL GAS. 

Throughout the Santa Maria district wherever any oil has been found 
it is invariably accompanied by considerable quantities of natural 
gas; indeed, this form of hydrocarbon is somewhat more widely dis¬ 
tributed than the oil, occurring in many places in the shale above the 
oil zones and in some wells which have yielded no petroleum. The pres¬ 
sure of the gas varies from zone to zone and from well to well. The 
greatest pressure so far recorded was in Hartnell well No. 1, where, 
according to Mr. Orcutt, it was over 400 pounds per square inch dur¬ 
ing the initial flow of oil and gas. Most of the gas is utilized for the 
generation of heat or of power direct in gas engines. Some of it is 
utilized for domestic purposes in the field and the immediate vicinity. 

ASPHALT. 

Great deposits of asphalt are associated with the petroleum-bearing 
and later formations over certain portions of the Santa Maria dis¬ 
trict. The asphalt (in the broader sense of the word) within the 
district occurs in several different ways—as veins penetrating the 
Monterey shale and later formations; as impregnations of the shale, 
sands, or gravels in or overlying the Monterey; and as more or less 
impure effusions at the surface. The more important deposits are in 
the hills northwest of Arroyo Grande; in the region of Asphaltum 
and La Zaca creeks, east of Sisquoc; in Graciosa Ridge; and in the 
vicinity of Redrock Mountain. These deposits have been described 































TECHNOLOGY OF PRODUCTION AND UTILIZATION. 


119 


in detail by George H. Eldridge,® and are mentioned at various places 
throughout this bulletin; further discussion of them is therefore 
unnecessary. 

TECHNOLOGY OF PRODUCTION AND UTILIZATION. 

OIL COMPANIES OF THE SANTA MARIA DISTRICT. 

The following is a statement of the oil operations in the Santa 
Maria district, compiled from all data available up to January 1, 
1907 : 

Oil companies and wells in Santa Maria district. 


Oil wells. 


Company. 


Field. 


Produc¬ 


tive. 


Anglo-Californian Oil Syndicate. 

Associated Oil Co. 

Barca Oil Co. 

Brookshire Oil Co. 

California Coast Oil Co. 

California Coast Oil Co. (Union Oil Co.)_ 

Calif or nia-Newlove Oil Co. 

Casmalia Ranch Oil and Development Co.. 

Claremont Oil Co. 

Coast Line Oil Co. 

Coblentz Oil Co... 

Crown Oil Co. 

Crystal Oil Co. 

Diamond Oil Co. 

Dome Oil Co. 

Graciosa Oil Co. 

Hall & Hall Oil Co. 

La Grande Oil Co. 

Laguna Land Co. 

Lompoc Oil Developing Co. 

Los Alamos Oil and Development Co. 

Las Flores Land and Oil Co. 

McNee Oil Co. 

Meridian Oil Co. 

National Oil and Transportation Co. (As¬ 
sociated Oil Co.). 

New Huasna Oil Co. 

Oak Park Oil Co. 

Pennsylvania Oil Co. 

Perpetual Oil Co.. 

Pacific Oil and Transportation Co. (Asso¬ 
ciated Oil Co.). 

Palmer Oil Co. 

Pinal Oil Co. 

Radium Oil Co. 

Recruit Oil Co. (Escolle and Newhall). 

Rice Ranch Oil Co. 

Santa Barbara Oil Co. 

Santa Lucia Oil Co. 

Santa Maria Oil Co. (Union Oil Co.). 

Santa Maria Oil and Gas Co. (Union Oil Co.) 

Santa Ynez Valley Development Co. 

Southern Pacific Co. 

Standard Oil Co. (pipe lines, storage, etc.).. 

Stillwell Oil Co. 

Syndicate Oil Co. (Union Oil Co.). 

The Oil Co. 

Tiber Oil Co. 

Todos Santos Oil Co. 

Traders’ Union Oil Co. 

Union Oil Co.: 

Burton lease. 

Eefson lease. 

Folsom lease... 


Lompoc. 

Arroyo Grande... 

Lompoc. 

Santa Maria. 

_do. 

-do. 

Arroyo Grande... 

Santa Maria. 

_do. 

Lompoc. 

Santa Maria. 

Arroyo Grande... 

-do. 

Santa Maria. 

_do. 

_do. 

_do. 

Arroyo Grande... 

_do. 

Lompoc. 

_do. 

Santa Maria. 

Arroyo Grande... 

Santa Maria. 

_do. 

Arroyo Grande... 

_do. 

Santa Maria. 

Arroyo Grande... 
Santa Maria. 

_do. 

_do. 

_do. 

_do. 

_do. 

Santa Ynez. 

Arroyo Grande... 

Santa Maria. 

_do. 

Santa Ynez. 

Santa Maria. 

_do. 

_do. 

_do. 

_do. 

Arroyo Grande... 

Lompoc. 

Santa Maria. 

Lompoc. 

_do. 

Santa Maria. 


4 


3 


1 

6 

1 


1 


1 

11 


2 


1 

4 


1 


2 

5 


Aban¬ 

doned. 


1 

&1 

1 


1 
b 1 
1 


2 


1 


1 



1 


1 


1 

1 


1 


Drilling. 


Total. 


1 1 

1 1 

1 

1 6 

1 

3 


1 


1 


1 

1 

1 


1 

2 

1 

1 

1 


1 

1 

2 

1 

1 

1 

1 


2 

8 

2 

1 

1 


3 


1 

1 

1 

1 

1 

1 

1 


1 

1 

1 

1 

1 

2 

1 

1 


3 


2 

1 

1 

1 

2 

3 


1 

14 

1 

4 

3 

1 

I 

3 

8 


1 1 


1 

2 


1 

1 

3 

1 

1 


1 

1 

3 


1 

4 

8 


a The asphalt and bituminous rock deposits of the United States: Twenty-second Ann. Rept. U. S. 
Geol. Survey, part 5, 1901, pp. 209-452, pis. 25-58, figs. 1-52. 
b Water well. r 








































































































































120 


SANTA MARTA OIL DISTRICT, CALIFORNIA. 

Oil companies and wells in Santa Maria district —Continued. 




Oil wells. 

Company. 

. Field. 

Produc¬ 

tive. 

Aban¬ 

doned. 

Drilling. 

Total. 

Union Oil Co.—Continued. 

Fox lease. 

Santa Maria. 

5 


1 

6 

Hartnell lease. 

.do..•_ 

2 

a\ 

1 

4 

Hill lease. 

Lompoc. 

2 

1 

1 

4 

Hobbs lease. 

Santa Maria. 

8 


2 

10 

Newlove. 

.do. 


5 

5 

Wise & Denigan 

Lompoc. 

8 



8 

Waldorf well 

Santa Maria. 

1 


1 

Western Union Oil Co.. 

.do. 

26 

3 

2 

31 

Yakima Oil Co. (Lucas) (Associated Oil 
Co.). 

. .do. 

1 


1 







94 

25 

55 

174 


WELL DRILLING. 

The wells in the Santa Maria district are among the deepest oil 
producers in the world, one of them reaching a depth of over 4,400 
feet. Except at three or four wells, where rotary drills have been 
used to penetrate the soft sands and shales near the surface, all of 
the drilling has been done with the standard rig. The casing used 
ranges in diameter from 12 to 16 inches at the top down to 41 inches, 
and in some wells, it is believed, even smaller, at the bottom. The 
cost of the deeper wells runs in general from $12,000 to $20,000, 
but several of the deepest are said to have cost even more than the 
latter figure. 

Owing to the close texture of the shale, it is usually possible to 
carry the hole down for a considerable distance below the casing 
without danger of caving. Wherever the wells penetrate the soft 
Fernando beds for any considerable distance much trouble is expe¬ 
rienced, but otherwise the drilling in the field is said to be as a rule 
comparatively easy. 

PRODUCTION. 

The production of oil in the Santa Maria region has been increas¬ 
ing rapidly in the last four or five years, but the figures of actual 
production do not fully indicate the increase in the capacity of the 
district. Lack of storage capacity, inadequate transportation facili¬ 
ties, and the low price of crude petroleum are factors which have 
kept down the amount produced and marketed. Well drilling has 
been going on steadily ever since the field was opened, but only a few 
companies have pushed their production up to the limit for any 
length of time. 

Nearly all of the oil so far produced in the district has come from 
the Santa Maria field. The production of the district, including the 
Santa Maria, Lompoc, and Arroyo Grande fields, for the last five 
years is as follows: 













































TECHNOLOGY OF PRODUCTION AND UTILIZATION. 


121 


Production of crude petroleum in Santa Maria oil district, 1902—1906 .« 

[Barrels of 42 gallons each.] 


1902 .• 99,283 

1903 . 178,140 

1904 . 1,367,174 

1905 . 2, 565, 96G 

1906 . 4,906,513 


9,117, 076 

The estimated maximum capacity of the district January 1, 1907, is 
40,400 barrels per day. 

STORAGE CAPACITY. 

The storage facilities of the district consist of steel and wooden 
tanks and open earthern reservoirs. The reservoirs are located 
only in the field and are used only temporarily or in cases of emer¬ 
gency. The total storage capacity of the district, not including the 
open reservoirs, is 1,464,000 barrels. 

TRANSPORTATION FACILITIES. 

The oil from the Santa Maria district is distributed by means of 
pipe lines, tank cars, and some of it eventually by tank steamers. 
The principal pipe lines of the district are four connecting the field 
with Port Harford and one running from the Western Union wells 
to Gaviota. The rail lines available are the Southern Pacific at 
Gaviota, Casmalia, and Betteravia, and the Pacific Coast at Carreaga 
and Orcutt. Tank steamers of the Associated, Standard, and Union 
oil companies take the product from Port Harford or Gaviota. 

The following is a summary of the principal pipe lines in the 
district: 

Pipe lines in Santa Maria oil district. 


Company. 

From— 

To— 

Distance. 

rrkoct Oil Transport C!o 

Graciosa wells . 

Oil Port . 

Miles. 

34 


W ells . 

Casmalia . 

8 

T.no A lamns Oil «nrl T)pivelor>ment Co.. 

.do . 

Carreaga . 

Pacific Oil and Transportation Co . 

Orcutt ... 

Gaviota . 

51 

Pinal and Brookshire oil companies .. . 

Wells. 

Graciosa station. 

2 

r»n . 

.do. 

Betteravia. 

7 


Orcutt . 

Port Harford . 

32 

Do . 

Western Union wells . 

Orcutt . 

7 

Do . 

Hall, Dome, Pinal, and 

. do . 

3 

S+amltirrl Oil Cn. ('2 lines'! 

Brookshire wells. 

Pacific Coast Oil Co.’s 

Port Harford . 


tanks. 

Orcutt . 

. do . 

32 

Ho . 

. do . 

. do ... 

32 

Do . 

Lompoc field . 

Orcutt . 

16 

Do . 

Escolle and Santa Maria 

. do . 

3 

On . 

Oil and Gas Co.’s wells. 
Fox, Hobbs, Folsom, and 
other wells. 

Reservoirs Nos. 1, 2, and 3.. 

. do . 

3 


. do . 

4 


Wells . 

Carreaga. 

4 






a Compiled from data furnished by the different operating companies. 







































































122 


SANTA MARIA OIL DISTRICT, CALIFORNIA. 
REFINERIES. 


The principal refineries utilizing the oil from the Santa Maria dis¬ 
trict are as follows: 

California Petroleum Refineries , Limited. —The refinery of this 
newly organized company is now in course of erection at Oil Port, 
south of Port Harford. It is said that the initial capacity of this 
refinery will be about 7,000 barrels per day, and that all the usual 
products will be refined. 

Pacific Oil Transportation Company. —The refinery of this com¬ 
pany is located at Gaviota, and consists of nine stills with a capacity 
of 1,050 barrels of crude oil per day. The principal products are 
illuminants and fuel residue. 

Standard Oil Company. —The plant of this company is located at 
Point Richmond, Contra Costa County, and is said to consist of 19 
stills with a capacity of 5,000 barrels of crude oil and 4,000 barrels 
re-run per day. The products are illuminants, lubricants, and coke. 

Union Oil Company of California.— The main refinery of this com¬ 
pany is located at Oleum, Contra Costa County, and consists of a 
number of stills capable of producing illuminants, distillate, and 
asphalt. 

UTILIZATION OF THE OIL. 


Most of the oil from the Santa Maria district is refined, the lighter 
products being used for illuminants and for the direct generation of 
power in gas engines, and the heavier products and unrefined heavy 
oil for fuel, lubricants, road dressing, etc. With the exception of 
a very small amount used locally, all the oil is sent out of the district, 
the greater part of the product at present, it is believed, going to the 
refineries near San Francisco. Contracts recently made in South 
America, Japan, and the Hawaiian Islands indicate that within a 
short time much of the product of the district will be exported. 

11ESUME. 

The Santa Maria oil district, comprising the Santa Maria, Lompoc, 
Arroyo Grande, and Huasna fields, occupies the central and northern 
portions of the Lompoc and Guadalupe quadrangles, northern Santa 
Barbara County; the southern part of the San Luis quadrangle, 
southern San Luis Obispo County, and a small part of the unmapped 
area between the Lompoc and San Luis quadrangles. 

The* larger part of the district is a basin region inclosed between 
two divisions of the Coast Ranges—the San Rafael and Santa Ynez 
mountains—and the Pacific Ocean. The formations in this basin 
have undergone less disturbance than in the mountains and the con¬ 
ditions in it are good for the accumulation of oil. 


RESUME. 


123 


The formations involved in the geology of the district include the 
Franciscan (Jurassic?) sandstone, shale, glaucophane schist, jasper, 
and intruded serpentine; Knoxville (lower Cretaceous) conglomerate, 
sandstone, and shale; pre-Monterey (which may include both Cre¬ 
taceous and older Tertiary) conglomerate, sandstone, and shale; 
Tejon (Eocene) sandstone, shale, and conglomerate; Vaqueros (lower 
Miocene) conglomerate, sandstone, and shale; Monterey (middle 
Miocene) diatomaceous and flinty shale, limestone, calcerous shale, 
and volcanic ash; Fernando (Miocene-Pliocene-Pleistocene) con¬ 
glomerate, sandstone, and shale; and Quaternary gravel, sand, clay, 
and alluvium. The sedimentary formations of Tertiary and early 
Quaternary age have a combined maximum thickness of at least 
13,200 feet. 

A variety of igneous rocks of Cretaceous and Tertiary age, mostly 
intrusive, outcrop over small areas. 

The Monterey shale (middle Miocene) is the original and chief 
oil-bearing formation, the petroleum having originated and remained 
in it in large quantities. Some has escaped by seepage and collected 
in the overlying Fernando formation or the Quaternary terrace de¬ 
posits, or has been dissipated. The oil is supposed to accumulate in 
fractured zones and porous sands in the lower portion of the Monterey, 
where brittle shale predominates, anticlines furnishing the most favor¬ 
able conditions for accumulation. The Monterey shale is in large 
part of organic origin, being especially rich in diatoms, and the oil 
is supposed to be a product of the plant and animal remains inclosed 
in it. The quantity of these remains originally deposited with this 
formation is sufficient to account for a vast amount of derived oil. 

Two structural systems prevail in the district, the features in the 
northeastern portion striking northwest and southeast, those in the 
southern portion striking east and west, and those in the intervening 
region trending in a direction intermediate between the two. Few 
faults of importance were noted in the field. The productive terri¬ 
tory lies in a region of more or less gentle folds in the central part of 
the area, most of the wells being located along or near anticlines. 

The wells range in depth from 1,500 to more than 4,000 feet. In 
the Santa Maria and Lompoc fields they obtain oil from zones of 
fractured shale, and possibly in certain places from sandy layers in 
the lower portion of the Monterey formation. The production of the 
individual wells ranges from 5 to 3,000 barrels per day, the average 
being between 300 and 400 barrels. The oil ranges in gravity from 
19° to 35° Baume, the greater part of it being about 25° to 27°. In 
the Arroyo Grande field the oil comes from sandstone at the base 
of the Fernando and is of 14° gravity. There is in all these fields 
much undeveloped territory which offers great promise of being 


124 SANTA MARIA OIL DISTRICT, CALIFORNIA. 

highly productive. The conditions affecting the presence of oil have 
been discussed for individual areas and those places enumerated in 
which the conditions seem favorable for its accumulation. 

There are 52 oil companies interested in the district; 11 of these 
own all the producing wells. Of the 174 wells in the district 94 are 
productive, 55 are drilling, and 25 are abandoned. The total pro¬ 
duction of the field up to January 1, 1907, was 9,117,076 barrels; the 
production for 1906 alone was 4,906,513 barrels. 


PLATES XII TO XXVI 














PLATE XII.- 


Tejon (Eocene) Fossils. 

(Unless otherwise indicated all figures are natural size.) 

Fig. 1. Cardium brewerii Gabb. Type. Right valve; altitude 61 mm. View of exte¬ 
rior. Pal. California, vol. 1, 1869, pi. 24, fig. 155. A common species in 
the Eocene of the Santa Ynez Mountains. 0 

Fig. 2a. Crassatellites collina Conrad. U.S.N.M. 165312. Left valve; longitude 87 
mm. View of exterior. San Julian ranch (4507). Characteristic of this 
horizon. 

Fig. 2b. View of anterior end of same specimen. 

Fig. 3. Crass stellites collina Conrad. U.S.N.M. 165312. Hinge. Same localitv as 
fig. 2. 

Fig. 4. Pecten ( Chlamys) yneziana Arnold. U.S.N.M. 165313. Paratype. Altitude 
52 mm. View of exterior. San Julian ranch (4507). Characteristic of 
this horizon. 

Fig. 5a. Ficus mamillatus Gabb. U.S.N.M. 165319. Altitude 31 mm. View of back. 
North of Sudden (4518). Characteristic of this horizon. 

Fig. 5 b. View of top of same specimen. 

Fig. 6. Turritella uvasana Conrad. U.S.N.M. 165327. Altitude of imperfect speci¬ 
men 25 mm. Aperture view. North of Sudden (4578). Characteristic 
of this horizon. 


126 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XII 





TEJON (EOCENE i FOSSILS. 


' L 










PLATE XIII. 

Knoxville (Cretaceous) and Tejon (Eocene) Fossils. 

(Unless otherwise indicated all figures are natural size.) 

Fig. 1. Aucella piochii Gabb. U.S.N.M. 30831. Right valve; altitude 25 mm. View 
of exterior. Knoxville (lower Cretaceous) formation, East Fork Tepus- 
cpiet Creek (4173). Characteristic of the lower Cretaceous throughout 
the Coast Ranges. 

Fig. 2. Aucella piochii Gabb. U.S.N.M. 30831. Left valve; altitude 15 mm. View 
of exterior, X 2. Same locality and horizon as fig. 1. 

Fig. 3a. Aucella piochii Gabb. Left valve; altitude 27 mm. View of exterior. Bull. 
U. S. Geol. Survey No. 133, 1895, pi. 4, fig. 6. 

Fig. 35. Exterior of right valve of same specimen. Op. cit., pi. 4, fig. 7. 

Fig. 4. Venericardia planicosta Lamarck, U.S.N.M. 164973. Left valve; longitude 84 
mm. Eocene, Little Falls, Wash. This is the most widespread and 
characteristic Eocene species in the world. 

Eig. 5a. Turritella (martinezensis Gabb) var. f lompocensis Arnold. Paratype. Alti¬ 
tude of fragment, 30 mm. Back view. Same locality as fig. 8. 

Fig. 55. Basal view of same specimen. 

Fig. 6a. Pecten (Chlamys) yneziana Arnold. U.S.N.M. 165313. Type. Right valve; 

altitude 64 mm. View of exterior. San Julian ranch (4507). Charac¬ 
teristic of this horizon. 

Fig. 65. Same species. Length of hinge of right valve 25 mm. 

Fig. 7. Turritella uvasana Conrad. U.S.N.M. 165326. Altitude of imperfect specimen 
68 mm. Aperture view. San Julian ranch (4507). Characteristic of 
the Eocene throughout the Coast Ranges. 

Fig. 8. Turritella (martinezensis Gabb) var. f lompocensis Arnold. U.S.N.M. 165316. 

Type. Longitude 68 mm. View of back. Southwest of Lompoc (4509). 


128 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XIII 



KNOXVILLE (CRETACEOUS) AND TEJON (EOCENE) FOSSILS. 







PLATE XIY. 

Tejon (Eocene) Pelecypoda. 

(Unless otherwise indicated all figures are natural size.) 

Fig. la. Ostrea idriaensis Gabb. U.S.N.M. 165318. Left valve; altitude 114 mm. 

View of exterior. North of Sudden (4518). Characteristic of this 
horizon. 

Fig. lb. View of exterior of right valve of same specimen. 

Fig. 2. Phacoides cumulata Gabb. U.S.N.M. 165328. Right valve; altitude 10 mm. 

View of exterior, X 4. Three miles north of Sudden (4518); also known 
from type locality of Tejon formation. 


13G 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XIV 



TEJON (EOCENE) PELECYPODA 


PLATE XV. 

Vaqueros (Lower Miocene) Fossils. 

(Unless otherwise indicated all figures are natural size.) 

Fig. la. Purpura vaquerosensis Arnold. Collection of Delos Arnold. Type. Alti¬ 
tude 100 nun Aperture view. Lynchs Mountain, Monterey County, Cal. 
Fig. 16. Back view of same specimen. 

Fig. 2. Modiolus yneziana Arnold. U.S.N.M. 165324. Type. Right valve; altitude 
31mm. View of exterior, X 2. San Julian ranch (4504 ). Characteristic 
of this horizon. 


132 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XV 



VAQUEROS (LOWER MIOCENE) FOSSILS. 



PLATE XVI. 

Vaqueros (Lower Miocene) Fossils. 

(Unless otherwise indicated all figures are natural size.) 

Fig. 1 . Pecten (. Lyropecten ) magnolia Conrad. U.S.N.M. 165317. Right valve; alti¬ 
tude 155 mm. View of exterior, X b San Julian ranch. A character¬ 
istic Vaqueros species. 

Fig. 2. Ostrea eldridgei Arnold. U.S.N.M. 165307. Left valve; altitude 100 mm. 

View of exterior. Mouth of Ballard Canyon, 2 miles south of Santa Ynez 
(4478). Characteristic of this horizon. 

Fig. 3. Turrilella ineziana Conrad. U.S.N.M. 165321. Altitude 120 mm. View of 
side. Ten miles west of Santa Ynez (4514). Characteristic of this hori¬ 
zon throughout the Coast Ranges. 

134 


u. s. geological survey 


BULLETIN NO. 322 


PL. XVI 



5jgs ' Jfjr 


Jr 

•f** Jr 

1 i ' IlfPl 


VAQUEROS (LOWER MIOCENE FOSSILS 




PLATE XVII. 

Yaqueros (Lower Miocene) Peleoypoda and Brachiopoda. 

(Unless otherwise indicated all figures are natural size.) 

Fig. 1 . Pecten ( Pecten ) vanvlech Arnold. U.S.N.M. 165305. Type. Right valve; 

altitude 64 mm. View of exterior. Mouth of Ballard Canyon, 2 miles 
south of Santa Ynez (4478). Characteristic of this horizon. 

Fig. 2. Pecten ( Pecten) vanvlecki Arnold. U.S.N.M. 165306. Paratype. Left valve; 

altitude 72 mm. View of exterior. Mouth of Ballard Canyon, 2 miles 
south of Santa Ynez (4478). Characteristic of this horizon. 

Fig. 3. Pecten ( Chlamys ) sespeensis var. hydei Arnold. U.S.N.M. 165308. Left valve; 

altitude 60 mm. View of exterior. Mouth of Ballard Canyon, 2 miles 
south of Santa Ynez (4478). Characteristic of this horizon. 

Fig. 4a. Terebratalla kennedyi Ball. U.S.N.M. 165325. Type. Ventral valve; alti¬ 
tude 26 mm. View of exterior. Lime quarry 5 miles southwest of 
Lompoc (4521). Characteristic of this horizon. 

Fig. 4b. Dorsal valve of same species; altitude of fragment 18 mm. View of exte¬ 
rior. 

Fig. 4c. Dorsal valve of same species; altitude 19 mm. View of exterior. 

Fig. 4 d. Ventral valve of same species; altitude 28 mm. View of exterior. 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XVII 






4 


a 




VAQUEROS (LOWER MIOCENE) PELECYPODA AND BRACHIOPODA. 







PLATE XVIII. 

Vaqueros (Lower Miocene) Pelecypoda. 

(Unless otherwise indicated all figures are one-half natural size.) 

Fig. 1. Pecten (Lyropecten) crassicardo Conrad. U.S.N.M. 164967. Exterior of valve, 
showing characteristic sculpture; altitude 90 mm. Ojai Valley, Ven¬ 
tura County, Cal. This species ranges throughout the Miocene, being 
commoner in the lower part in southern California, in the upper part in 
central California. 

Fig. 2. Pecten ( Amusium ) lompocensis Arnold. Collection of California Academy of 
Sciences. Holotype. Mold of interior of left valve; altitude 105 mm. 
Four miles south of Lompoc. 

Fig. 3. Pecten ( Amusium) lompocensis Arnold. U.S.N.M. 164852. Paratype. Inte¬ 
rior of a portion of left valve; altitude 90 mm. Ojai Valley, Ventura 
County, Cal. 

Fig. 4. Pecten ( Amusium) lompocensis Arnold. Collection of California Academy of 
Sciences. Paratype. Imperfect mold of interior of right valve; hinge 
line 42 mm. Same locality as fig. 2. 

Fig. 5. Pecten ( Lyropecten) bowersi Arnold. Collection of University of California. 

Type. Exterior of slightly imperfect right valve; altitude 150 mm. 
Santa Ynez Canyon. 

Fig. 6a. Ostrea eldridgei Arnold. U.S.N.M. 165320. Left valve; altitude 114 mm. 

View of exterior. El Jaro Creek (4519). Characteristic of this horizon. 

Fig. 66. View of exterior of right valve of same specimen. 

138 



BULLETIN NO. 322 PL. XVIII 


U. S. GEOLOGICAL SURVEY 


VAQUEROS (LOWER MIOCENE) PELECYPODA. 








PLATE XIX. 

Monterey (Middle Miocene) Diatoms. 

Fig. 1. Photomicrograph of slide of partially cleaned diatomaceous shale material 
from the Lompoc quadrangle, X 100. All the larger individuals and 
fragments are Coscinodiscus oculus iridis Ehrenberg. 

Fig. 2. Photomicrograph of slide of diatoms from the Monterey shale at Santa Monica, 
Los Angeles County, Cal , X 00. Nearly all the species shown on this 
slide occur in the diatomaceous deposits in the Santa Maria district. 


140 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XIX 





tmxfil 


MONTEREY (MIDDLE MIOCENE) DIATOMS. 


1784—Bull. 322—07-10 





PLATE XX. 

Monterey (Middle Miocene) Diatoms. 

Fig. la. Actinoptychus undulatus Ehrenberg. 

Fig. lb. Lithodesmium cornigcrum Brim. 

Fig. lc. Dictyocha gracilis (not a diatom; nature unknown). Enlargement to 1,000 
diameters of a portion of the slide shown in PI. XIX, fig. 1. 

Fig. 2. Coscinodiscus obscurus A. S., X 1,000. From the Monterey shale of the Santa 
Maria district. 

Fig. 3. Coscinodiscus subtilis Ehrenberg, X 1,000. From the Monterey shale of the 
Santa Maria district. 

Fig. 4. Coscinodiscus robustus Grev., X 1,000. From the Monterey shale of the Santa 
Maria district. 


142 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XX 



MONTEREY (MIDDLE MIOCENE) DIATOMS. 













PLATE XXI. 

Fernando (Pliocene) Gasteropoda. 

(Unless otherwise indicated figures are natural size.) 

Fig. 1. Trochita radians Lamarck. U.S.N.M. 165310. Maximum diameter of fragment 
20 mm. View of top, X 2. Fugler Point asphalt mine, near Gary (4475). 
Characteristic of the upper Miocene and lower Pliocene of this region. 
Fig. 2. Priene oregonensis Redfield (young). U.S.N.M. 165262. Altitude 46 mm. 

Aperture view. Waldorf asphalt mine (4473). Also known recent. 
Fig. 3. Lunatia lewisii Gould. U.S.N.M. 165264. Young specimen; altitude 23 mm. 

Aperture view, X 2. Waldorf asphalt mine (4473). Also known recent. 
Fig. 4. Thalotia caffca Gabb. U.S.N.M. 165298. Latitude 29 mm. Back view. 

Fugler Point asphalt mine, near Gary (4475). Also known recent. 

Fig. 5. Thalotia caffea Gabb. U.S.N.M. 165297. Latitude of fragment 21 mm. View 
of side of fragment, slightly tilted up. Same locality as fig. 4. 

Fig. 6. Lymnsea alamosensis Arnold. U.S.N.M. 165426. Type. Altitude 6 mm. 

Aperture view, X 6. Fresh-water beds, 1 mile southeast of bench mark 
425, Los Alamos Valley. 

Fig. 7. Lymnsea alamosensis Arnold. U.S.N.M. 165426. Young specimen; altitude 
3.5 mm. Same localitv as fig. 6. 

Fig. 8. Cadulus fusiformis Sharp and Pilsbry. U.S.N.M. 165267. Longitude 10 
mm. Side view, X 3. Waldorf asphalt mine (4473). Known also recent . 
Fig. 9. Cancellaria crawfordiana Dali var. fugler % Arnold. U.S.N.M. 165322. Type. 

Altitude 22.5 mm. Aperture view, X 2. Fugler Point asphalt mine, 
near Gary (4475). Characteristic of this horizon. 

Fig. 10. Ocinehra mieheli Ford var. waldorfensis Arnold. U.S.N.M. 165261. Type. 

Altitude 11 mm. Aperture view, X 3. Waldorf asphalt mine (4473). 
Fig. 11. Turritella cooperi Carpenter. U.S.N.M. 165273. Altitude 34 mm. Aper¬ 
ture view, X 2. Waldorf asphalt mine (4473). Common in the Pliocene 
and Pleistocene. 

Fig. 12. Drillia waldorfensis Arnold. U.S.N.M. 165270. Type. Altitude 18.5 mm. 

Aperture view of imperfect specimen, X 2. Waldorf asphalt mine (4473). 
Characteristic of this horizon. 

Fig. 13. Drillia johnsoni Arnold. U. S. N.M. 165263. Altitude 34 mm. Back view, 
X 2. Waldorf asphalt mine (4473). Also found fossil at San Pedro. 

Fig. 14a. Neverita recluziana Petit. U.S.N.M. 165323. Altitude 35 mm. Aperture 
view. Fugler Point asphalt mine near Gary (4475). Also known 
recent. 

Fig. 146. View of base of same specimen. 

Fig. 15. Neverita recluziana Petit. U.S.N.M. 165299. Altitude 20 mm. Aperture 
view, X 2. Fugler Point asphalt mine, near Gary (4475). Also known 
recent. 

Fig. 16. Natica clausa Broderip and Sowerby. U.S.N.M. 165269. Altitude 21 mm. 

Aperture view, X 2. Waldorf asphalt mine (4473). Also known recent. 
Fig. 17. Nassa waldorfensis Arnold. U.S.N.M. 165272. Type. Altitude 13 mm. 

Aperture view, X 2. Waldorf asphalt mine ('4473). Characteristic of 
this horizon. 

Fig. 18. Drillia graciosana Arnold. U.S.N.M. 165309. Type. Altitude 14 mm. 

Aperture view, X 3. Graciosa Ridge, near Oreutt (4476). Character¬ 
istic of this horizon. 


144 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XXI 



FERNANDO (PLIOCENE) GASTEROPODA. 


PLATE XXII. 

Fernando (Pliocene) Fossils. 

(Unless otherwise indicated all figures are natural size.) 

Fig. la. Pholadidea ovoidea Gould. U.S.N.M. 165277. Longitude 58 mm. View of 
valve. Waldorf asphalt mine (4473). Also known recent. 

Fig. 16. View of hinge region of both valves. 

Fig. 2. Purpura crispata Chemintz. U.S.N.M. 165278. Altitude 20 mm. Aperture 
view. One mile north of Schumann (4474). Also known recent. 

Fig. 3a. Leda taphria Dali. U.S.N.M. 165296. Longitude 10.5 mm. View of exte¬ 
rior, X 3. Fugler Point asphalt mine, near Gary (4475). Also known 
recent. 

Fig. 36. View of hinge region of both valves. 

Fig. 4a. Terebratalia occidentalis Dali. U.S.N.M. 165300. Ventral valve; latitude 
30 mm. View of exterior. Fugler Point asphalt mine, near Gary 
(4475). A variable species. Also known recent. 

Fig. 46. View of dorsal valve of same specimen. 

Fig. 5. Macoma nasuta Conrad. U.S.N.M. 165276. Longitude 47 mm. View of 
right valve. Waldorf asphalt mine (4473). Also known recent and in 
Miocene. 

Fig. 6. Phacoides nuttalli Conrad var. antecedens Arnold. U.S.N.M. 165290. Type. 

Left valve; longitude 23 mm. View of exterior, X 2. Alcatraz asphalt 
mine, near Sisquoc (4471). Characteristic of this horizon. 

Fig. 7. Cryptomya ovalis Conrad. LT.S.N.M. 165289. Left valve; longitude 23 mm. 

Alcatraz asphalt mine, near Sisquoc (4471). Characteristic of this 
horizon. 

Fig. 8. Dosinia ponderosa Gray. U.S.N.M. 165295. Right valve; altitude 105 mm. 

View of exterior, X h- Alcatraz asphalt mine, near Sisquoc (4471). 
Also known recent. 

Fig. 9. Leda orcutti Arnold. U.S.N.M. 165271. Type. Longitude 7 mm. View of 
exterior, X 3. Waldorf asphalt mine (4473). Characteristic of this 
horizon. 

Fig. 10. Tapes tcnerrima Carpenter. U.S.N.M. 165293. Left valve; longitude 83 
mm. View of exterior. Alcatraz asphalt mine, near Sisquoc (4471). 
Common in the Pliocene Also known recent. 


146 


U. S. GEOLOGICAL SURVEY 



ftWm 

ytttmi'J 




BULLETIN NO. 322 PL. XXII 


FERNANDO (PLIOCENE) FOSSILS. 














PLATE XXIII. 

Fernando (Pliocene) Fossils. 

(Unless otherwise indicated all figures are natural size.) 

Fig. 1 . Spisula sisquocensis Arnold. U.S.N.M. 165292. Type. Left valve; longi¬ 
tude 120 mm. View of exterior, X h • Alcatraz asphalt mine, near 
Sisquoc (4471). Characteristic of this horizon. 

Fig. 2. Clidiophora punctata Carpenter. U.S.N.M. 165302. Right valve; longitude 
36 mm. View of exterior. Graciosa Ridge, near Orcutt (4476). Also 
known recent. 

Fig. 3. Clidiophora punctata Carpenter. U.S.N.M. 165283. Left valve; longitude 
35 mm. View of interior. Graciosa Ridge, near Orcutt (4476). Also 
known recent. 

Fig. 4. Venericardia californica Dali. U.S.N.M. 165274. Altitude 29 mm. Aperture 
view. Waldorf asphalt mine (4473). Characteristic of this horizon. 

Fig. 5. Cumingia californica Conrad. U.S.N.M. 165311. Left valve; longitude 17 
mm. View of exterior, X 2. Fugler Point asphalt mine, near Gary 
(4475). Also known recent. 

Fig. 6. Spisula catilliformis Conrad var. alcatrazensis Arnold. U.S.N.M. 165291. 

Type. Right valve; longitude 128 mm. View of exterior, X Alca¬ 
traz asphalt mine, near Sisquoc (4471). Characteristic of this horizon. 

Fig. 7. Bathytoma carpenteriana Gabb var. fernandoana Arnold. U.S.N.M. 165303. 

Type. Altitude 24 mm. Aperture view. Graciosa Ridge, near Orcutt 
(4476). Characteristic of this horizon. 

Fig. 8. Phacoides annulatus Reeve. U.S.N.M. 165286. Right valve; longitude 45 
mm. View of exterior. One mile north of Schumann (4474). Common 
in the Fernando and also found recent. 

Fig. 9a. Phacoides intensus Dali. U.S.N.M. 165260. Left valve; altitude 6.5 mm. 

View of exterior, X 4. Waldorf asphalt mine (4473). Found also in 
same horizon at San Diego. 

Fig. 96. View of interior of same specimen, X 4. 

Fig. 10. Ostrea veatchii Gabb. U.S.N.M. 165282. Left valve; altitude 96 mm. View 
of exterior. One mile north of Schumann (4474). Characteristic of this 
horizon. 


148 



<J. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XXIII 


FERNANDO (PLIOCENE) FOSSILS. 





PLATE XXIY. 

Fernando (Pliocene) Fossils. 

(Unless otherwise indicated all figures are natural size.) 

Fig. 1 . Crepidula princeps Conrad. U.S.N.M. 165268. Longitude 76 mm. Side 
view. Waldorf asphalt mine (4473). Known only in the fossil state, 
and found in Santa Barbara County only in the Fernando formation, 
although it is known from the lower Miocene farther north. 

Fig. 2. Crepidula princeps Conrad. U.S.N.M. 165315. Longitude 106 mm. View of 
interior, showing deck. Packards Hill, Santa Barbara. 

Fig. 3. Aslyris richthofeni Gabb. U.S.N.M. 165266. Altitude 14 mm. Aperture 
view, X 2. Waldorf asphalt mine (4473). So far known only as fossil. 

Fig. 4. Nassa californiana Conrad. U.S.N.M. 165304. Altitude 30 mm. Aperture 
view. Graciosa Ridge, near Orcutt (4477). Characteristic of this 
horizon in the Santa Maria district. 

Fig. 5. Area trilineata Conrad. U.S.N.M. 165301. Left valve; longitude 46 mm. 

View of exterior. Fugler Point asphalt mine, near Gary (4475). Com¬ 
mon in the Fernando and equivalent formations and also found in the 
Monterey. 

Fig. 6. Echinarachvius ashleyi Merriam. U.S.N.M. 165259. Maximum diameter 69 
mm. View from above. Graciosa Ridge, near Orcutt (4469). 

Fig. 7. Echinarachnius ashleyi Merriam. U.S.N.M. 165259. Maximum diameter 47 
mm. View from below. Same locality as fig. 6. 

Fig. 8. Echinarachnius excentricus Esclischoltz var. U.S.N.M 165285. Maximum 
diameter 41 mm. View of top. One mile north of Schumann (4474). 
This variety is probably characteristic of this horizon. 


150 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 


PL. XXIV 



FERNANDO (PLIOCENE) FOSSILS. 








PLATE XXY. 

Fernando (Pliocene) Pectens. 

(Unless otherwise indicated all figures are two-thirds natural size.) 

Fig. la. Pecten ( Pecten) stearnsii Dali. U.S.N.M. 148008. Right valve; altitude 
87 mm. View of exterior. San Diego formation (Pliocene), Pacific 
Beach, San Diego County, Cal. Common in the Fernando formation 
of southern California. 

Fig. 16. Same specimen as fig. la. Exterior of left valve. 

Fig. 2 a. Pecten (Patinopecten) oweni Arnold. Collection of University of California. 

Type. Right valve, anterior ear slightly broken; altitude 85 mm. 
View of exterior. Foxen’s ranch. Characteristic of this horizon. 

Fig. 26. Same specimen as fig. 2a. Exterior of left valve. 

Fig. 3. Pecten ( Chlamys) lawsoni Arnold. Collection of California Academy of Science. 

Type. Right valve (umbo and ears missing); longitude 65 mm. View 
of exterior. One mile north of Schumann. Characteristic of this 
horizon. 

Fig. 4. Pecten ( Chlamys ) wattsi Arnold. Collection of California Academy of Science. 

Type. Slightly imperfect left valve; altitude 66 mm. View of exte¬ 
rior. Lower Pliocene, Kreyenhagen’s ranch, Fresno County. Common 
in the Fernando of southern California. 

Fig. 5. Pecten hcmphilli Dali. U.S.N.M. 165280. Left valve; altitude 22.50 mm. 

View of exterior, X !§• One mile north of Schumann (4474). C'harac- 
acteristic of this horizon. 


152 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XXV 



FERNANDO (PLIOCENE) PECTENS 
















PLATE XXYI. 

Fernando (Pliocene) Pecten. 

(Unless otherwise indicated all figures are two-thirds natural size.) 

Fig. 1. Pecten ( Patinopecten) healeyi Arnold. U.S.N.M. 148012. Holotype. Right 
valve; altitude 121 mm. View of exterior. San Diego formation (Pli¬ 
ocene), San Diego County, Cal. Characteristic of the Fernando forma¬ 
tion throughout the Coast Range. 

Fig. 2. Pecten ( Patinopecten) healeyi Arnold. U.S.N.M. 154162. Paratype. Left 
valve; altitude 141 mm. View of exterior. San Diego formation (Pli¬ 
ocene), Pacific Beach, San Diego County, Cal. 


154 


U. S. GEOLOGICAL SURVEY 


BULLETIN NO. 322 PL. XXVI 



FERNANDO (PLIOCENE) PECTENS. 























, 




■ 


















INDEX. 


A. 

Page. 


Acknowledgments to those aiding. 10 

Acteon sp., occurrence of. 58 

Actinoptychus undulatus Ehr., figure show¬ 
ing. 142 

undulatus Ehr., occurrence of. 41 

Alcatraz asphalt mine, location of. s .... 78 

view of. 78 

Alkalinity, origin of. 37 

Alluvium, occurrence and description of_ 64 

Alumina in Monterey shale, origin of. 41 

Amphissa sp., occurrence of. 58 

Amusium lompocensis Arnold, figure show¬ 
ing. 138 

lompocensis Arnold, occurrence of. 32 

Anderson, Frank M., work of. 92 

Anderson, Robert, and Arnold, Ralph, 

work of. 9,14 

Andrews, E. B., on occurrence of oil. 71 

Angulus sp., occurrence of. 58 

Anticlinal theory, explanation of.... 71-72 

Anticlines, relation of oil and.'..72-74 

Antisell, Thomas, on geology of region.. 10-11,51 

Antonio, oil near. 83 

Arachnodiscus, occurrence of. 40 

ehrenbergii var. californica, occurrence 

of. 41 

Area trilineata Conrad, figure showing. 150 

trilineata Conrad, occurrence of.47,58 

sp., occurrence of.-. 58 

Area of region. 15 

Arnold, Ralph, and Anderson, Robert, work 

of. 9,14 

Arroyo Grande, asphalt near. 118 

Arroyo Grande field, development in. 14 

geology of.:. 107-108 

oil of. 108-109 

structure of. 108 

Ash, volcanic. See Volcanic ash. 

Asphalt deposits, occurrence of. 12, 

78-79,82,84-85,88,96,98,103,105,118-119 

occurrence of, mode of. 74 

Asphaltum Creek, asphalt near. 118 

Astyris richtofeni Gabb, figure showing.... 150 

richtofeni Gabb, occurrence of. 58 

Aucella piochii Gabb, figure showing. 128 

piochii Gabb, occurrence of. 28 

B. 

Bagg, R. M., fossils found by. 39 

Balanus concavus Bronn, occurrence of.... 58 

estrellanus Conrad, occurrence of. 32 

Basalt, occurrence of.64-66 


Page. 

Bathytoma carpinteria Gabb var. fernan- 


doana Arnold, figure showing.. 148 

carpinteria Gabb var. fernandoana Ar¬ 
nold, occurrence of. 58 

tryoniana Gabb, occurrence of. 58 

Bittium arnoldi Bartsch, occurrence of.... 58 

casmaliaensis Bartsch, occurrence of... 58 

Bitumen, burning of. 48-52 

geologic position of. 109-110 

Blake, fossils near.58-60 

Blake, W. P., Monterey shale named by_ 33 

Borsonia sp., occurrence of. 59 

Boyer, C. S., fossils determined by.40-41 

Brachiopoda, plate showing. 136 

Branner, J. C., on Monterey shale. 39-40 

Brookshire-IIartnell area, description of.. 99-101 

Buckhorn Canyon, geology in. 31 

Burnt shale, description of.48-52 

occurrence of. 49,82,106 

oil in. 74-75 

origin of. 48-49 

view of. 36 

Burton Mesa, description of.'....7.22-23 

diatomaceous earth on. 38 

geology on. 62 

oil in. 84,91 

structure of.83-84 

C. 

Cadulus fusiformis Sharp and Pilsbry, 

figure showing. 144 

fusiformis Sharp and Pilsbry, occur¬ 
rence of. 58 

California Coast Co., lease of, fossils from.. 57-60 

Calliostoma sp., occurrence of. 58 

Callista subdiaphana Carpenter, occurrence 

of. 58 

Campbell, A. EL, work of. 10 

Canada Arena, oil near. 89-90 

Cancellaria craw-fordiana Dali var. fugleri 

Arnold, figure showing. 144 

crawfordiana Dali var. fugleri Arnold, 

occurrence of. 58 

sp., occurrence of. 58 

Cardium brewerii Gabb, figure showing.... 126 

brew r erii Gabb, occurrence of. 32 

meekianum Gabb, occurrence of. 58 

quadrigenarium Conrad, occurrence of.. 32 

sp., occurrence of. 58 

Casmalia, diatomaceous earth near. 38 

diatomaceous earth near, view of. 36 

monocline near, view of. 80 

unconformity near, view of. 78 


1784—Bull. 322—07-11 


155 















































































156 


INDEX. 


Page. 

Casmalia Hills, definition of. 16 

description of. 19-20 

fossils of.57-00 

geology at and near. 30,49,56,57,03-04,68 

oil in. 82-83 

structure of.81-82 

upheaval of. 69 

Chico formation, correlation of. 27 

Chione mathewsonii Gabb, occurrence of... 32 

sp., occurrence of. 58 

Chlamys lawsoni Arnold, figure showing. .. 152 

lawsoni Arnold, occurrence of. 59 

sespeensis var. hydei Arnold, figure 

showing.j. 136 

var. hydei Arnold, occurrence of- 32 

yneziana Arnold, figure showing.126,128 

occurrence of. 32 

Chlorostoma sp., occurrence of. 58 

Chrysodomus sp., occurrence of. 58 

Clarke, F. W., on age of oil. 113 

Clidiophora punctata Carpenter, figure 

showing. 148 

punctata Carpenter, occurrence of. 58 

Climate, description of.,. 26 

Coast terraces, description of. 23-24,25 

Codakia sp., occurrence of. 32 

Columnar section, plate showing. 26 

Contour map of Santa Maria field. 92 

preparation of. 92-93 

Conus hornii Gabb, occurrence of. 32 

sp., occurrence of. 32 

Cooper, H. N., analyses by. 115-117 

Coscinodiscus heteropurus Ehr., occurrence 

of. 41 

marginatus Ehrenberg occurrence of... 40,41 

marginatus Ehrenberg var. intermedia 

Rathay, occurrence of. 40,41 

nodulifer Janish, occurrence of. 41 

obscurus A. S., figures showing. 142 

occurrence of. 41 

oculus iridis Ehr., figure showing. 140 

occurrence of. 41 

radiatus Ehr., occurrence of. 41 

robustus Grev., figure showing. 142 

occurrence of. 40,41 

subtilis Ehr., figure showing. 142 

occurrence of. 41 

Crassatelites collina Conrad, figure showing. 126 

collina Conrad, occurrence of. 32 

sp., occurrence of. 32 

Crepidula pnneeps Conrad, figure showing. 150 

princeps Conrad, occurrence of. 58 

Cretaceous rocks, character of. 27 

description of. 28 

fossils in, plate showing. 128 

occurrence of. 12 

Cretaceous time, history in. 66 

Crucibulum spinosum Sowerby, occurrence 

of. 58 

Cryptomya ovalis Conrad, figure showing .. 146 

ovalis Conrad, occurrence of. 58 

Cuaslui Creek, fossils near. 58-60 

oil near. 90 

Cumingiacaliformca Conrad, figure showing 148 

californica Conrad, occurrence of. 58 

Cuyama River, geology on. 35 

volcanic ash on, view of. 34 


D. Page. 

Development, future, probabilities of. 79-80, 

86,88,90,91 

Developments, present, detailed descriptions 

of.92-109 

Diabase, occurrence of. 65 

Diatomaceous earth, description of. 38 

occurrence of.3&-34,35,38,54-55,89 

views of. 34,36 

Diatoms, occurrence and character of... 38-39,68 

oil from. HO 

plates showing. 140-142 

See also Diatomaceous earth. 

Dictyoclia gracilis, figure showing. 142 

Diploneis, occurrence of. 40 

Divide, geology near. 54 

Dosinia elevata Gabb, occurrence of ---- 32 

ponderosa Gray, figure showing. 146 

occurrence of. 58 

Drainage, description of. 25 

Drillia graciosana Arnold, figure showing .. 144 

graciosana Arnold, occurrence of. 58 

johnsoni Arnold, figure showing. 144 

occurrence of. 58 

waldorfensis Arnold, figure showing.... 144 

occurrence of. 58 

Drilling, cost of. 120 

Dune sand, occurrence and description of.. 63-64 

E. 


Ecliinarachnius aslileyi Merriam, figure 

showing. 150 

ashleyi Merriam, occurrence of. 58 

excentricus Esch. var., figure showing.. 150 

occurrence of. 58 

El Jaro Creek, fossils at. 40 

Monterey shale on. 35,39 

analysis of. 45 

Eldridge G. H., on geology of region_ 13-14,50 

Eocene rocks, character of. 27 

description of. .. 29-33 

fossils in, plates showing. 126,128,130 

Eocene time, history in. 66-67 

Escolle-Pinal-Folsom-Santa Maria Oil and 

Gas area, description of. 98-99 

F. 

Fairbanks, II. W., on geology of region_ 11-13, 

31,39,40,64-65,108 

Faults, occurrence of. 77-78,85,105 

Fernando formation, age of. 57-60 

contact of Monterey and, topographic 

expression of. 22 

character of. 54-55 

correlation of. 27,52 

deposition of. 69-70 

description of.’. 52-60 

diatomaceous earth in. 54-55 

view of. 98 

distribution of. 52,57 

fossils of. 57-60 

plates showing. 144-154 

name of. 52 

oil in. 53 

structure of. 56-57 

terrace deposits and, similarity of. 61-62 

thickness of. 52 











































































































INDEX 


157 


Page. 

Fernando formation, topography on. 25 

view of. 46 

Ficus mamillatus Gabb, figure showing_ 126 

mamillatus Gabb, occurrence of. 32 

Field work, period and extent of. 9 

Figueroa Creek, Fernando gravel on, view 

of. 46 

Folsom-Santa Maria Oil and Gas-Escolle- 

Pinal area, description of.98-99 

Foraminifera, occurrence of. 39-40 

oil from. 110 

Ford, H. C., on burning of shale. 48 

Fossils, occurrence and character of. 28, 

32-33,58-60,110-111 

plates showing. 126-154 

Fox-Hobbs-Pinal area, description of.96-97 

Franciscan formation, character of. 27 

description of. 27-28 

Fugler Point, asphalt at. 78 

fossils near. 57-60 

oil near. 79-80,91 

Fusus occidentalis Gabb, occurrence of. 32 

sp., occurrence of. 58 

G. 

Galerus inornatus Gabb, occurrence of. 58 

Gary, asphalt near. 78 

oil near. 91 

Gas, occurrence of. 95,96,98,104,106,118 

oil flows due to. 73-74 i 

Gasteropod sp., occurrence of. 32 ! 

Gasteropoda, plate showing. 144 

Gato, Canada del, oil in and near.89-90 

Gato Ridge anticline, oil on. 89-90,91 

structure of.88-89 

Geography of region, outline of. 15-16 

Geologic history, outline of. 66-71 

Geologic map of Santa Maria district... Pocket 

accuracy of. 9 

Geologic sections, plate showing. 74 

Geology, bibliography of. 10-14 

columnar section showing. 26 

description of.26-71 

previous investigation of. 10-14 

Glycymeris barbarensis Conrad, occurrence 

of. 58 

veatchii Gabb var. major Stanton, oc¬ 
currence of. 32 

Graciosa Ridge, asphalt on.88,118 

diatomaceous earth on. 38 

view of. 98 

fire in. 48,51 

geology on and near. 49,63 

Graciosa wells, fossils near.57-60 

view at. 80 

Graciosa-Western Union area, description 

of. 101,103 

Guadalupe quadrangle, part of region in- 15 

Gypsum, occurrence of. 37 

H. 

Hall-Hobbs-Rice ranch area, description of. 94-96 

Harris, geology near. 52 

Harris Canyon, fossils near. 57-60 

Hartnell anticline, relations of. 87 


Hartnell-Brookshire area,description of.. 99-101 


Page. 

Hartnell well No. 1, gas pressure in. 118 

saddle at, view of. 98 

yield on. 101 

Hill wells, fossils near.57-60 

yield of. 105 

| History, outline of. 14 

History, geologic, outline of.66-71 

Hobbs-Pinal-Fox area, description of.96-97 

Hobbs-Rice ranch-Hall area, description of. 94-96 

Horsetown formation, correlation of. 27 

Howard Canyon, fossils near.57-60 

oil near. 91 

Iluasna field, development in. 14,109 

structure in. 109 

Hunt, Sterry, on occurrence of oil. 71 

I. 

Igneous rocks, description of.64-66 

intrusion of.66,69 

J. 

Jurassic rocks, character of. 27 

description of.27-28 

K. 

Keeley, F. J., fossils determined by. 40 

on putrefaction of diatoms. 112 

Kennerlia sp., occurrence of. 58 

Knoxville formation, character of. 27 

description of. 28 

fossils of, plate showing. 128 

L. 

La Zaca Creek, asphalt near. 118 

oil and asphalt on. 86 

La Zaca Creek-Lisque Creek anticline, oil in. 91 

structure of.90-91 

Labrea Creek, asphalt on. 78 

Laguna Seca, Canada, fossils near.57-60 

Leda orcutti Arnold, figure showing. 146 

orcutti Arnold, occurrence of. 58 

taphria Dali, figure showing. 146 

occurrence of. 58 

Lithodesmium cornigerum Brun, figure 

showing. 142 

cornigerum Brun, occurrence of. 41 

Location of region. 15 

Lompoc, development near. 14 

diatomaceous earth near. 38 

geology near. 36 

oil near. 80 

structure near. 80 

Lompoc field, description of. 104-107 

geology of. 106 

oil in. 106-107 

structure of. 104-105 

Lompoc quadrangle, part of region in. 15 

Lompoc terrace, definition of. 16 

Los Alamos Valley, description of. 21 

geology in and near. 13,55,56 

Lospe, Mount, altitude of. 19 

geology of. 28 

Lucapina crenulata Sowerby, occurrence of. 58 

Lunatia lewisii Gould, figure showing. 144 

occurrence of. 58 














































































































158 


INDEX 


Page. 


Lyrrmsea alaraosensis Arnold, figures show¬ 
ing. 144 

alarnosensis Arnold, occurrence of. 59 

Lyropecten bowersi Arnold, figure showing. 138 

bowersi Arnold, occurrence of. 32 

crassicardo Conrad, figure showing. 138 

occurrence of. 32 

magnolia Conrad, figure showing. 134 

occurrence of. 32 

M. 

McKay and Mulholland development by... 14 

Macoma nasuta Conrad, figure showing.... 146 

nasuta Conrad, occurrence of. 59 

secta Conrad, occurrence of. 59 

sp., occurrence of. 59 

Mactra uvasana Conrad, occurrence of. 32 

sp., occurrence of. 59 

Mann, Albert, on origin of oil. 110-111 

Map of Santa Maria field. 92 

contours of. 92-93 

preparation of. 93 

Map, geologic and structural, of Santa 

Maria district. Pocket 

Martinez formation, correlation of. 27 

Melosira sulcata Ehr., occurrence of. 40 

Merced formation, correlation of. 27 

Meretrix uvasana Conrad, occurrence of.... 32 

sp., occurrence of. 32 

Metamorphism of Monterey shale, by heat... 48-52 

by water. 45-47 

Miltha sp., occurrence of. 32 

Miocene rocks, character of. 27 

description of.29-52 

fossils in, plate showing. 132-142 

occurrence of. 12-13 

Miocene time, history in.67-69 

Miopleiona oregonensis Dali, occurrence of. 59 

Modelo formation, correlation of. 27 

Modiolus rectus Conrad, occurrence of. 59 

yneziana Arnold, figure showing. 132 

occurrence of. 32 

Monia macroschisma Deshayes, occurrence 

of. 59 

Monterey shale, age of.33,47 

alkalinity of. 37 

alteration of, by water. 45-47 

analyses of. 45 

burning of. 48-52 

See also Burnt shale. 

character of.33-34 

chemical composition of.44-45 

contact of Fernando and, topographic 

expression of. 22 

correlation of. 27 

deposition of.68-69 

description of. 33-52 

diatomaceous earth in. 33-34,35,38 

distribution of. 33 

divisions of, descriptions of.34-38 

folds and faults in. 76-78 

folds in, view of. 46 

fossils in.39-43 

plates showing. 140,142 

intrusions in.65-66 

materials of.38-43 


Page. 

Monterey shale, mechanical composition 


of. 38-44 

metamorphism of, by burning.48-52 

microscopic appearance of. 43-44 

monocline in, view of. 80 

name of. 33 

oil in.33,123 

See also Oil. 

outcrops of, views of.34,36 

structure of. 47,76-91 

thickness of. 47 

topography on.24-25 

views of. 36 

Mount Solomon anticline, description of... 87-88 

See also Solomon, Mount. 

Muricidea sp., occurrence of. 59 

Mussel Rock, oil near. 83 

Mya truncata Linn6, occurrence of. 59 

Mytilus mathewsonii Gabb, occurrence of.. 32 

sp., occurrence of. 59 

N. 

Nassa californiana Conrad, figure showing.. 150 

californiana Conrad, occurrence of. 59 

waldorfensis Arnold, figure showing_ 144 

occurrence of. 59 

Natica clausa Broderip and Sowerby, figure 

showing. 144 

clausa Broderip and Sowerby, occur¬ 
rence of. 59 

Neverita recluziana Petit, figure showing. . 144 

recluziana Petit, occurrence of. 59 

sp., occurrence of. 32 

Newlove anticline, character of. 101-102 

Nucula truncata Gabb, occurrence of. 32 

O. ‘ 

Oak Canyon, bitumen in. 84 

Ocinebra lurida Middendorf, occurrence of.. 59 

micheli Ford var. waldorfensis Arnold, 

figure showing. 144 

var. waldorfensis Arnold, occurrence 

of. 59 

Oil, age of. 113 

analyses of. 115-118 

burning of. 48-52 

character of.. 95,97,99,101,102,104,107-109,123 

chemical properties of. 114-118 

color of. 114 

distillation of. 116 

flow of, causes of. .'. . 72-73 "* 

future development of. 79-80,86,88,90,91 

gas and, relations of. 73-74 

gravity of.9,114,123 

migration of.72-73 

occurrence of, conditions affecting.71-91 

indications of. 74-75, 

78,81,82-83,85,88,89-91 

theory of.71-72 

odor of. 114 

origin of. 109-113,123 

physical properties of. 113-114 

refineries for. 122 

storage of. 121 

transportation of. 121 

utilization of. 122 

viscosity of. 114,116 









































































































INDEX. 


159 


Page. 

Oil companies, list of. 119-120 

number of. 124 

Oil fields, detailed descriptions of.92-109 

See also particular fields. 

Oil wells, character of. 123 

drilling of. 120 

geology of. 94-95 

oil of. 95,97,99,101,102,104,123 

yield of. 9,96,97,99-104,107,109,120-121,123,124 

Oil zones, character of. 73,93-102,104 

geologic position of. 94,106-107 

Olivella biplicata Sowerby, occurrence of... 59 

intorta Carpenter, occurrence of. 59 

O’Neill, Edmond, analyses by. 117-118 

on Santa Maria oil. 117 

Opalia anomala Stearns, occurrence of. 59 

varicostata Stearns, occurrence of. 59 

Orcutt, fossils near. 58-60 

Oreutt, W. W., work of. 87 

Orogenic movements, occurrence of.66-70 

Ostreaeldridgei Arnold, figure showing... 134,138 

eldridgei Arnold, occurrence of. 32 

idrisensis Gabb, figure showing. 130 

occurrence of. 32 

veatchii Gabb, figure showing. 148 

occurrence of. 59 

sp., occurrence of. 32 

P. 

Panomya ampla Dali, occurrence of. 59 

Panopea generosa Gould, occurrence of. 59 

Patinopecten healeyi A mold,figure showing. 154 

healeyi Arnold, occurrence of. 59 

oweni Arnold, figure showing. 152 

occurrence of. 59 

Pecten (Lyropecten) bowersi Arnold, figure 

showing. 138 

(Lyropecten) bowersi Arnold, occur¬ 
rence of. 32 

(Plagioctenium) cerrocensis Gabb, oc¬ 
currence of. 59 

(Lyropecten) crassicardo Conrad, figure 

showing. 138 

occurrence of. 32 

(Patinopecten) healeyi Arnold, figure 

showing. 154 

occurrence of. 59 

(Pecten) hemphilli Dali, figure showing. 152 

occurrence of. 59 

(Chlamys) lawsoni Arnold, figure show¬ 
ing. 152 

occurrence of. 59 

(Amusium) lompocensis Arnold, figure 

showing. 138 

occurrence of. 32 

(Lyropecten) magnolia Conrad, figure 

showing. 134 

occurrence of. 32 

(Patinopecten) oweni Arnold, figure 

showing. 152 

occurrence of... 59 

(Chlamys) sespeensis var. hydei Arnold, 

figure showing. 136 

occurrence of. 32 

(Pecten) stearnsii Dali, figure showing. 152 
occurrence of. 59 


Page. 

Pecten vauvlecki Arnold, figure showing ... 136 

occurrence of. 32 

(Pecten) wattsi Arnold, figure showing. 152 

occurrence of. 59 

(Chlamys) yneziana Arnold, figure 

showing. 126,128 

occurrence of. 32 

Pectens, plates showing. 152,154 

Pelecypoda, plates showing. 130,136,138 

Phacoides acutilineatus Conrad, occurrence 

of. 47 

annulatus Reeve, figure showing. 148 

occurrence of. 59 

cumulata Gabb, figure showing. 130 

occurrence of. 32 

intensus Dali, figure showing. 148 

occurrence of. 59 

nuttallii Conrad var. antecedens Ar¬ 
nold, figure showing. 146 

var. antecedens Arnold, occurrence 

of. 59 

(Miltha) sp., occurrence of. 32 

Pholadidea ovoidea Conrad, figure showing. 146 

ovoidea Conrad, occurrence of. 59 

sp., occurrence of. 59 

Pinal-Folsom-Santa Maria Oil and Gas- 

Escolle area, description of.98-99 

Pinal-Fox-Hobbs area, description of.96-97 

Pinal Oil Co., development by. 14 

Pine Canyon anticline, description of. 83 

Pipe lines, location of. 121 

Plagioctenium cerrocensis Gabb, occurrence 

of. 59 

Platyodon cancellatus Conrad var., occur¬ 
rence of. 59 

Pleistocene deposits, character of..... 27 

terraces of. See Terraces. 

Pleistocene time, history in. 70 

Pleurotoma (Borsonia) sp., occurrence of.. 59 

Pliocene rocks, character of. 27 

fossils in, plates showing. 144-154 

Pliocene shells, occurrence of. 13-14 

Point Sal Ridge, definition of. 16 

geology of. 12-13,65 

Population, number of. 15 

Price Canyon, oil in. 107 

Priene oregonensis Redfield (Young), figure 

showing. 144 

oregonensis Redfield (Young), occur¬ 
rence of. 59 

var. angelensis Arnold, occurrence 

of. 59 

Production, amount of. 9,96,97, 

99-104,107,109,120-121 

Prutzman, P. W., analyses by. 115,117 

Purisima formation, correlation of. 27 

Purisima Hills, asphalt in. 85 

definition of. 16 

description of. 21-22 

diatomaceous earth in. 38,54-55 

geology in. 56 

oil in. 84-86,91 

structure of. 84-85 

Purpura crispata Chemnitz, figure showing. 146 

crispata Chemnitz, occurrence of. 59 

Putrefaction, rate of, influence of, on pro¬ 
duction of oil. 112 





































































































1(50 


INDEX 


Q. Page- 

Quaternary deposits, character of. 27 

description of. 60-64 

Quaternary terraces, description of 23-24,25,60-63 
Quaternary time, history in. 69-71 

R. 

Radiolaria, occurrence of. 39,40 

Railroads, access by. 15 

Rainfall, amount of. 25-26 

Redrock Mountain, altitude of. 22,49 

asphalt near.85,118 

geology on. 49 

oil on. 86 

Refineries, statistics of. 122 

Relief, description of. 16-25 

R4sum6 of paper. 122-124 

Rice ranch-Hobbs-Ilall area, description of. 94-96 
Rincon Volcano, duration of. 49 

S. 

Salsipuedes Creek, fossils at. 40 

Monterey shale on.35,39 

analysis of. 45 

geology on. 62 

San Antonio terrace, definition of. 16 

diatomaceous earth in. 38 

oil in. 82-83,91 

structure of.'.81-82 

San Lorenzo formation, correlation of. 27 

San Luis formation, correlation of. 27 

San Pablo formation, correlation of. 27 

San Pedro formation, correlation of. 27 

San Rafael Mountains, definition of. 15 

description of. 17 

geology of. 30,31,35,55,65,68 

oil in, evidence of. 78 

future development of. 79-80 

structure of. 76-78 

upheaval of. 69 

Sand, occurrence and description of.63-64 

Santa Lucia Canyon, oil near. 91 

Santa Maria field, contours of. .*.92-93 

map of. 92 

discussion of.92-93 

oil zones in. 93-94 

wells of.93-104 

See also particular areas. 

Santa Maria Oil and Gas Co., lease of, fos¬ 
sils from. 57-60 

Santa Maria Oil and Gas-Escolle-Pinal-Fol- 

som area, description of.98-99 

Santa Maria Valley, description of. 19 

geology of. 62 

oil in. 91 

Santa Rita Hills, definition of. 16 

description of. 23 

diatomaceous earth in. 38 

geology in.35,57 

oil in. 81,91 

structure in_•..80-81 

Santa Rita Valley, geology in. 56 

Santa Ynez, diatomaceous earth near. 38 

oil near. 86 

Santa Ynez anticline, description of. 86 


Page. 


Santa Ynez Mountains, definition of. 15 

description of. 18-19 

geology of. 11-12, 29,31, 62, 66-67 

oil in. 80-81 

structure of.80-81 

upheaval of. 69 

Santa Ynez Valley, description of. 23 

Saxidomus gracilis Gould, occurrence of... 59 

sp., occurrence of. 59 

Scala sp., occurrence of. 59 

Schumann, fossils near. 57-60 

geology near. 54,82 

Schumann anticline, description of.81-82 

oil in. 91 

relations of. 87-88 

Schumann Canyon, geology near. 65 

oil near. 91 

Sea-urchin bed, fossils from. 57-60 

Sedimentary rocks, correlations of. 27 

description of. 26-64 

Serpentine, occurrence of. 65 

Sespe formation, character of. 29 

correlation of. 27 

description of. 29-33 

occurrence of. 29 

Shale, fractured, accumulation of oil in_73-74 

Sigaretus debilis Gould, occurrence of. 59 

Silica in Monterey shale, origin of. 41-42 

Silicification, effect of. 47 

Siliqua edentula Gabb, occurrence of. 59 

Sisquoc, asphalt near. 78 

fossils near. 57-60 

geology near. 54,56,65 

oil near. 79,91 

Sisquoc River, asphalt on. 78 

Monterey shale on, view of. 34 

Solen sicarius Gould, figure showing. 59 

sp., occurrence of. 32 

Solomon, Mount, altitude of. 20 

asphalt on. 88 

geology near. 54 

oil in.88,91 

structure of.87-88 

Solomon Hills, definition of. 16 

description of. 20-21 

geology of. 56 

Spisula catilliformis Conrad var. alcatraz- 

ensis Arnold, figure showing.... 148 

catilliformis Conrad var. alcatrazensis 

Arnold, occurrence of. 59 

sisquocensis Arnold, figure showing_ 148 

occurrence of. 59 

Sponge spicules, occurrence of. 42 

Structural map of Santa Maria district... Pocket 
Structure, detailed discussion of. 75-91,103-105,108 

lines of, convergence of. 18-19 

map showing. 92 

origin of. 75 

topography and, relations of.24-25 

T. 

Tapes lacineata Carpenter, occurrence of... 60 

staleyi Gabb, occurrence of. 60 

tenerrima Carpenter, figure showing... 146 

occurrence of. 60 
















































































































INDEX. 


161 


Page. 

Tejon formation, character of. 29 

correlation of. 27 

description of. 29-33 

fossils of. 31-32 

plates showing. 126,128,130 

Tellina bodegensis Hinds, occurrence of.... 60 

sp., occurrence of.32,60 

Tepusquet Creek, asphalt on. 78 

geology on.28,65 

oil near. 91 

Terebratalia kennedyi Dali, figure show¬ 
ing . 136 

occurrence of. 33 

occidentalis Dali, figure showing. 146 

occurrence of. 60 

Terraces, description of. 23-24,25,60-62 

origin of. 63 

Tertiary rocks, character of. 27 

Tertiary time, history in. 66-70 

Thalotia caffea Gabb, figure showing. 144 

occurrence of. 60 

Thracia trapezoides Conrad, occurrence of. 60 

Thyasira gouldii Philippi, occurrence of.... 60 

Topatopa formation, correlation of. 27 

Topography, description of. 16-26 

structure and, relations of.24-25 

Tresus nuttali Conrad, occurrence of. 60 

Tritonium sp., occurrence of. 60 

Trochita radians Lamarck, figure showing. 144 

radians Lamarck, occurrence of. 60 

sp., occurrence of. 60 

Trophonvaquerosensis Arnold, figure show¬ 
ing. 132 

vaquerosensis Arnold, occurrence of.... 33 

Turritella cooperi Carpenter, figure showing 144 

cooperi Carpenter, occurrence of. 60 

ineziana Conrad, figure showing. 134 

occurrence of. 33 

martinezensis Gabb var. lompocensis 

Arnold, figure showing. 128 

var. lompocensis Arnold, occurrence 

of. 32 

uvasana Conrad. 126,128 

occurrence of. 32 

variata Conrad, occurrence of. 33 

sp. occurrence of. 33 


U. Page. 

Unconformities, positions of. 27 

V. 


Vaqueros formation, character of.29,31 

correlation of. 27 

deposition of. 67 

description of.29-33 

fossils of.31-33 

plates showing/. 132-138 

Vegetation, description of. 26 

plates showing. 46,80 

Venericardia californica Dali, figure showing 148 

californica Dali, occurrence of. 60 

planicosta Lamarck, figure showing.... 128 

occurrence of. 32 

Volcanic ash, deposition of. 69 

occurrence of.30-31,37 

outcrop of, view of. 34 

' Volcanic eruptions, occurrence of. 68-69 

W. 

i Waldorf, fossils near. 57-60 

geology near. 54 

Water, artesian, presence of.72-73 

Wells, water in. 72-75,95-97,103 

See also Oil wells. 

Western Union anticline, description of... 87,103 

Western Union Oil Co., development by_ 14 

wells of, description of. 103-104 

fossils near_i. 57-60 

view at. 80- 

Western Union-Graciosa area, description 

of. 101-103 

White, I. C., on occurrence of gas.71-72 

Whitney, J. D., on geology of region. 11 

Wise & Denigan well, asphalt near. 85 


Z. 


Zaca Canyon, asphalt in. 78 

Zaca Creek, asphalt and oil on.85,86 

Zaca Lake, geology near. 27 

view near. 46 
































































































CLASSIFICATION OF THE PUBLICATIONS OF THE UNITED STATES GEOLOGICAL 

SURVEY. 

[Bulletin No. 322.] 

The publications of the United States Geological Survey consist of (1) Annual 
Reports, (2) Monographs, (3) Professional Papers, (4) Bulletins, (5) Mineral 
Resources, (6) Water-Supply and Irrigation Papers, (7) Topographic Atlas of United 
States—folios and separate sheets thereof, (8) Geologic Atlas of United States— 
folios thereof. The classes numbered 2, 7, and 8 are sold at cost of publication; the 
others are distributed free. A circular giving complete lists can be had on application. 

Most of the above publications can be obtained or consulted in the following ways: 

1. A limited number are delivered to the Director of the Survey, from whom they 
can be obtained, free of charge (except classes 2, 7, and 8), on application. 

2. A certain number are delivered to Senators and Representatives in Congress 
for distribution. 

3. Other copies are deposited with the Superintendent of Documents, Washington, 
D. C., from whom they can be had at prices slightly above cost. 

4. Copies of all Government publications are furnished to the principal public 
libraries in the large cities throughout the United States, where they can be con¬ 
sulted by those interested. 

The Professional Papers, Bulletins, and Water-Supply Papers treat of a variety of 
subjects, and the total number issued is large. They have therefore been classified 
into the following series: A, Economic geology; B, Descriptive geology; C, System¬ 
atic geology and paleontology; D, Petrography and mineralogy; E, Chemistry and 
physics; F, Geography; G, Miscellaneous; H, Forestry; I, Irrigation; J, Water stor¬ 
age; K, Pumping water; L, Quality of water; M, General hydrographic investiga¬ 
tions; N, Water power; O, Underground waters; P, Hydrographic progress reports; 
Q, Fuels; R, Structural materials. This paper is the one hundred and third in 
series A and the one hundred and twenty-seventh in series B, the complete lists of 
which follow (PP=Professional Paper; B=Bulletin; WS=Water-Supply Paper): 


SERIES A, ECONOMIC GEOLOGY. 

B 21. Lignites of Great Sioux Reservation: Report on region between Grand and Moreau rivers, 
Dakota, by Bailey Willis. 1885. 16 pp., 5 pis. (Out of stock.) 

B 46. Nature and origin of deposits of phosphate of lime, by R. A. F, Penrose, jr., with introduction by 
N. S. Shaler. 1888. 143 pp. (Out of stock.) 

B 65. Stratigraphy of the bituminous coal field of Pennsylvania, Ohio, and West Virginia, by I. C. 
White. 1891. 212 pp., 11 pis. (Out of stock.) 

B 111. Geology of Big Stone Gap coal field of Virginia and Kentucky, by M. R. Campbell. 1893. 106 pp., 
6 pis. (Out of stock.) 

B 132. The disseminated lead ores of southeastern Missouri, by Arthur Winslow. 1896. 31 pp. (Out 
of stock.) 

B 138. Artesian-well prospects in Atlantic Coastal Plain region, by N. H. Darton. 1896. 228 pp., 19 pis. 

B 139. Geology of Castle Mountain mining district, Montana, by W. H. Weed and L. V. Pirsson. 1896. 
164 pp., 17 pis. 

B 143. Bibliography of clays and the ceramic arts, by J. C. Branner. 1896. 114 pp. 

B 164. Reconnaissance on the Rio Grande coal fields of Texas, by T. W. Vaughan, including a report 
on igneous rocks from the San Carlos coal field, by E. C. E. Lord. 1900. 100 pp., 11 pis. (Out 
of stock.) 

B 178. El Paso tin deposits, by W. H. Weed. 1901. 15 pp., 1 pi. 


I 


II 


SERIES LIST. 


B 180. Occurrence and distribution of corundum in United States, by J. H. Pratt. 1901. 98 pp., 14 pis. 
(Out of stock; see No. 269.) 

B 182. A report on the economic geology of the Silverton quadrangle, Colorado, by F. L. Ransome. 

1901. 266 pp., 16 pis. (Out of stock.) 

B 184. Oil and gas fields of the western interior and northern Texas Coal Measures and of the Upper 
Cretaceous and Tertiary of the western Gulf coast, by G. I. Adams. 1901. 64 pp., 10 pis. (Out 
of stock.) 

B 193. The geological relations and distribution of platinum and associated metals, by J. F. Kern]). 

1902. 95 pp., 6 pis. 

B 198. The Berea grit oil sand in the Cadiz quadrangle, Ohio, by W. T. Griswold. 1902. 43 pp., 1 pi. 
(Out of stock.) 

PP 1. Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the 
geology of southeastern Alaska, by A. II. Brooks. 1902. 120 pp., 2 pis. 

B 200. Reconnaissance of the borax deposits of Death Valley and Mohave Desert, by M. R. Campbell. 

1902. 23 pp., 1 pi. (Out of stock.) 

B 202. Tests for gold and silver in shales from western Kansas, by Waldemar Lindgren. 1902. 21 pp. 
(Out of stock.) 

PP 2. Reconnaissance of the northwestern portion of Seward Peninsula, Alaska, by A. J. Collier. 1902. 
70 pp., 11 pis. 

PP 10. Reconnaissance from Fort Hamlin to Kotzebue Sound, Alaska, by way of Dali, Kanuti, Allen, 
and Kowak rivers, by W. C. Mendenhall. 1902. 68 pp., 10 pis. 

PP 11. Clays of the United States east of the Mississippi River, by Heinrich Ries. 1903. 298 pp., 9 pis. 
(Out of stock.) 

PP 12. Geology of the Globe copper district, Arizona, by F. L. Ransome. 1903. 168 pp., 27 pis. 

B 212. Oil fields of the Texas-Louisiana Gulf Coastal Plain, by C. W. Hayes and William Kennedy. 

1903. 174 pp., 11 pis. (Out of stock.) 

B 213. Contributions to economic geology, 1902; S. F, Emmons and C. W. Hayes, geologists in charge. 

1903. 449 pp. (Out of stock.) 

PP 15. The mineral resources of the Mount Wrangell district, Alaska, by W. C. Mendenhall and F. C. 
Schrader. 1903. 71 pp., 10 pis. 

B 218. Coal resources of the Yukon, Alaska, by A. J. Collier. 1903. 71 pp., 6 pis. 

B 219. The ore deposits of Tonopah, Nevada (preliminary report), by J. E. Spurr. 1903. 31 pp., 1 pi. 
(Out of stock.) 

PP 20. A reconnaissance in northern Alaska in 1901, by F. C. Schrader. 1904. 139 pp., 16 pis. 

PP 21. Geology and ore deposits of the Bisbee quadrangle, Arizona, by F L. Ransome. 1904. 168 pp., 
29 pis. 

B 223. Gypsum deposits in the United States, by G. I. Adams and others. 1904. 129 pp., 21 pis. (Out 
of stock.) 

PP 24. Zinc and lead deposits of northern Arkansas, by G. I. Adams. 1904. 118 pp., 27 pis. 

PP 25. Copper deposits of the Encampment district, Wyoming, by A. C. Spencer. 1904. 107 pp., 2 pis. 
(Out of stock.) 

B 225. Contributions to economic geology, 1903, by S. F, Emmons and C. W. Ilayes, geologists in charge. 

1904. 527 pp., 1 pi. (Out of stock.) 

PP 26. Economic resources of the northern Black Hills, by J. D. Irving, with contributions by S. F. 

Emmons and T. A. Jaggar, jr. 1904. 222 pp., 20 pis. 

PP 27. A geological reconnaissance across the Bitterroot Range and Clearwater Mountains in Montana 
and Idaho, by Waldemar Lindgren. 1904. 123 pp., 15 pis. 

B 229. Tin deposits of the York region, Alaska, by A. J. Collier. 1904. 61 pp., 7 pis. 

B 236. The Porcupine placer district, Alaska, by C. W. Wright. 1904. 35 pp., 10 pis. 

B 238. Economic geology of the Iola quadrangle, Kansas, by G. 1. Adams, Erasmus Haworth, and 
W. R. Crane. 1904. 83 pp., 11 pis. 

B 243. Cement materials and industry of the United States, by E. C. Eckel. 1905. 395 pp., 15 pis. 

B 246. Zinc and lead deposits of northwestern Illinois, by H. Foster Bain. 1904. 56 pp., 5 pis. 

B 247. The Fairhaven gold placers of Seward Peninsula, Alaska, by F. II. Moflit. 1905. 85 pp., 14 pis. 
B 249. Limestones of southeastern Pennsylvania, by F. G. Clapp. 1905. 52 pp., 7 pis. 

B 250. The petroleum fields of the Pacific coast of Alaska, with an account of the Bering River coal 
deposits, by G. C. Martin. 1905. 65 pp., 7 pis 

B 251. The gold placers of the Fortymile, Birch Creek, and Fairbanks regions, Alaska, by L. M. Prindle. 

1905. 89 pp., 16 pis. 

WS 117. The lignite of North Dakota and its relation to irrigation, by F. A. Wilder. 1905. 59 pp., 8 pis. 
PP 36. The lead, zinc, and fluorspar deposits of western Kentucky, by E. O. Ulrich and W. S. T. Smith. 
1905. 218 pp., 15 pis. 

PP 38. Economic geology of the Bingham mining district, Utah, by J. M. Boutwell, with a chapter on 
areal geology, by Arthur Keith, and an introduction on general geology, by S. F. Emmons. 
1905. 413 pp., 49 pis. 

PP 41. Geology of the central Copper River region, Alaska, by W. C. Mendenhall. 1905. 133 pp., 20 pis. 
B 254. Report of progress in the geological resurvey of the Cripple Creek district, Colorado, by Walde¬ 
mar Lindgren and F. L. Ransome. 1904, 36 pp. 


SERIES LIST. 


Ill 


B 255. The fluorspar deposits of southern Illinois, by H. Foster Bain. 1905. 75 pp., 6 pis. (Out of 
stock.) 

B 256. Mineral resources of the Elders Ridge quadrangle, Pennsylvania, by R. W. Stone. 1905. 
86 pp., 12 pis. 

B 259. Report on progress of investigations of mineral resources of Alaska in 1904, by A. H. Brooks 
and others. 1905. 196 pp., 3 pis. 

B 260. Contributions to economic geology, 1904; S. F. Emmons and C. W. Hayes, geologists in charge. 

1905. 620 pp., 4 pis. 

B 261. Preliminary report on the operations of the coal-testing plant of the United States Geological 
Survey at the Louisiana Purchase Exposition, St. Louis, Mo., 1904; E.W. Parker, J. A. Holmes, 
and M. R. Campbell, committee in charge. 1905. 172 pp. (Out of stock.) 

B 263. Methods and cost of gravel and placer mining in Alaska, by C. W. Purington. • 1905. 273 pp., 
42 pis. (Out of stock.) 

PP 42. Geology of the Tonopah mining district, Nevada, by J. E. Spurr. 1905. 295 pp., 24 pis. 

PP 43. The copper deposits of the Clifton-Morenci district, Arizona, by Waldemar Lindgren. 1905. 
375 pp., 25 pis. 

B 264. Record of deep-well drilling for 1904, by M. L. Fuller, E. F. Lines, and A. C. Veatch. 1905. 

106 pp. 

B 265. Geology of the Boulder district, Colorado, by N. M. Fenneman. 1905. 101 pp., 5 pis. 

B 267. The copper deposits of Missouri, by H. Foster Bain and E. O. Ulrich. 1905. 52 pp., 1 pi. 

B 269. Corundum and its occurrence and distribution in the United States (a revised and enlarged 
edition of Bulletin No. 180), by J. H. Pratt. 1906. 175 pp., 18 pis. 

PP 48. Report on the operations of the coal-testing plant of the United States Geological Survey at 
the Louisiana Purchase Exposition, St, Louis, Mo., 1904; E. W. Parker, J. A. Holmes, M. R. 
Campbell, committee in charge. 1906. (In three parts.) 1,492 pp., 13 pis. 

B 275. Slate deposits and slate industry of the United States, by T. N. Dale, with sections by E. C. 

Eckel, W. F. Hillebrand, and A. T. Coons. 1906. 154 pp., 25 pis. 

PP 49. Geology and mineral resources of part of the Cumberland Gap coal field, Kentucky, by G. H. 

Ashley and L. C. Glenn, in cooperation with the State Geological Department of Kentucky, 
C. J. Norwood, curator. 1906. 239 pp., 40 pis. 

B 277. Mineral resources of Kenai Peninsula, Alaska: Gold fields of the Turnagain Arm region, by 
F. H. Moffit; Coal fields of the Kachemak Bay region, by R. W. Stone. 1906. 80 pp., 18 pis.' 
B 278. Geology and coal resources of the Cape Lisburne region, Alaska, by A. J. Collier. 1906. 54 pp., 
9 pis. (Out of stock.) 

B 279. Mineral resources of the Kittanning and Rural Valley quadrangles, Pennsylvania, by Charles 
Butts. 1906. 198 pp., 11 pis. 

B 280. The Rampart gold placer region, Alaska, by L. M. Prindle and F. L. Hess. 1906. 54 pp., 7 pis. 
(Out of stock.) 

B 282. Oil fields of the Texas-Louisiana Gulf Coastal Plain, by N. M. Fenneman. 1906. 146 pp., 11 pis. 
PP 51. Geology of the Bighorn Mountains, by N. H. Darton. 1906. 129 pp., 47 pis. 

B 283. Geology and mineral resources of Mississippi, by A. F. Crider. 1906. 99 pp.,4 pis. 

B 284. Report on progress of investigations of the mineral resources of Alaska in 1905, by A. H. Brooks 
and others. 1906. 169 pp., 14 pis. 

B 285. Contributions to economic geology, 1905; S. F. Emmons and E. C. Eckel, geologists in charge. 

1906. 506 pp., 13 pis. (Out of stock.) 

B 286. Economic geology of the Beaver quadrangle, Pennsylvania, by L. H. Woolsey. 1906. 132 pp., 
8 pis. 

B 287. Juneau gold belt, Alaska, by A. C. Spencer, and A reconnaissance of Admiralty Island, Alaska, 
by C. W. Wright. 1906. 161 pp., 27 pis. 

PP 54. The geology and gold deposits of the Cripple Creek district, Colorado, by W. Lindgren and 

F. L. Ransome. 1906. 516 pp., 29 pis. 

PP 55. Ore deposits of the Silver Peak quadrangle, Nevada, by J. E. Spurr. 1906. 174 pp., 24 pis. 

B 289. A reconnaissance of the Matanuska coal field, Alaska, in 1905, by G. C. Martin. 1906. 34 pp., 
5 pis. 

B 290. Preliminary report on the operations of the fuel-testing plant of the United States Geological 
Survey at St. Louis, Mo., 1905, by J. A. Holmes. 1906. 240 pp. 

B 293. Reconnaissance of some gold and tin deposits of the southern Appalachians, by L. C. Graton, 
with notes on the Dahlonega mines, by W. Lindgren. 1906. 134 pp., 9 pis. 

B 294. Zinc and lead deposits of the upper Mississippi Valley, by H. Foster Bain. 1906. 155 pp., 16 pis. 
B 295. The Yukon-Tanana region, Alaska, description of Circle quadrangle, by L. M. Prindle. 1906. 
27 pp., 1 pi. 

B 296. Economic geology of the Independence quadrangle, Kansas, by Frank C. Schrader and 
Erasmus Haworth. 1906. 74 pp., 6 pis. 

B 297. The Yampa coal field, Routt County, Colo., by N. M. Fenneman, Hoyt S. Gale, and M. R. 
Campbell. 1906. 96 pp., 9 pis. 

B 298. Record of deep-well drilling for 1905, by Myron L. Fuller and Samuel Sanford. 1906. 299 pp. 
B 300. Economic geology of the Amity quadrangle in eastern Washington County, Pa., by Frederick 

G. Clapp. 1907. 145 pp., 8 pis. 


IV 


SERIES LIST. 


B 303. Preliminary account of Goldfield, Bullfrog, and other mining districts in southern Nevada, by 

F. L. Ransome, with notes on the Manhattan district, by G. H. Garrey and W. H. Emmons. 
1906. 98 pp., 5 pis. 

B 304. Oil and gas fields of Greene County, Pa., by Ralph W. Stone and Frederick G. Clapp. 1906. 110 
pp., 3 pis. 

PP 56. Geography and geology of a portion of southwestern Wyoming, with special reference to 
coal and oil, by A. C. Veatch. 1907. 178 pp., ‘26 pis. 

B 308. A geologic reconnaissance in southwestern Nevada and eastern California, by S. H. Ball. 1907. 
218 pp., 3 pis. 

B 309. The Santa Clara Valley, Puente Hills, and Los Angeles oil districts, southern California, by 

G. H.Eldridge and Ralph Arnold. 1907. 266 pp., 41 pis. 

B 312. The interaction between minerals and water solutions, with special reference to geologic 
phenomena, by E. C. Sullivan. 1907. 69 pp. 

B 313. The granites of Maine, by T. Nelson Dale, with an introduction by G. O. Smith. 1907. 202 pp., 
14 pis. 

B 314. Report of progress of investigations of mineral resources of Alaska in 1906, by A. H. Brooks 
and others. 1907. 235 pp., 4 pis. 

B 315. Contributions to economic geology, 1906, Part I: Metals and nonmetals, except fuels; S. F. 

Emmons and E. C. Eckel, geologists in charge. 1907. 504 pp., 4 pis. 

WS 215. Geology and water resources of a portion of the Missouri River Valley in northeastern 
Nebraska, by G. E. Condra. 1908. — pp., 11 pis. 

WS 216. Geology and water resources of the Republican River Valley in Nebraska and adjacent 
areas, by G. E. Condra. 1907. 71 pp., 13 pis. 

B 316 Contributions to economic geology, 1906, Part II: Coal, lignite, and peat. M. R. Campbell, 
geologist in charge. 1907. — pp., 23 pis. 

B 317. Preliminary report on the Santa Maria oil district, Santa Barbara County, Cal., by Ralph 
Arnold and Robert Anderson. 1907. 69 pp., 2 pis. 

B 318. Geology of oil and gas fields in Steubenville, Burgettstown, and Claysville quadrangles, Ohio, 
West Virginia, and Pennsylvania, by W. T. Griswold and M. J. Munn. 1907. 196 pp., 13 pis. 
B 320. The Downtown district of Leadville, Colo., by S. F. Emmons and J. D. Irving. 1907. 75 pp., 
7 pis. 

B 321. Geology and oil resources of the Summerland district, Santa Barbara County, Cal., by Ralph 
Arnold. 1907. 91 pp., 20 pis. 

B 322. Geology and oil resources of the Santa Maria oil district, Santa Barbara County, Cal., by Ralph 
Arnold and Robert Anderson. 1907. 161 pp., 26 pis. 

SERIES B, DESCRIPTIVE GEOLOGY. 

B 23. Observations on the junction between the Eastern sandstone and the Keweenaw series on 
Keweenaw Point, Lake Superior, by R. D. Irving and T. C. Chamberlin. 1885. 124 pp., 17 
pis. (Out of stock.) 

B 33. Notes on geology of northern California, by J. S. Diller. 1886. 23 pp. (Out of stock.) 

B 39. The upper beaches and deltas of Glacial Lake Agassiz, by Warren Upham. 1887. 84 pp., 1 pi. 
(Out of stock.) 

B 40. Changes in river courses in Washington Territory due to glaciation, by Bailey Willis. 1887. 10 
pp.,4 pis. (Oiit of stock.) 

B 45. The present condition of knowledge of the geology of Texas, by R. T. Hill. 1887. 94 pp. (Out 
of stock.) 

B 53. The geology of Nantucket, by N. S. Shaler. 1889. 55 pp., 10 pis. (Out of stock.) 

B 57. A geological reconnaissance in southwestern Kansas, by Robert Hay. 1890. 49 pp., 2 pis. 

B 58. The glacial boundary in western Pennsylvania, Ohio, Kentucky, Indiana, and Illinois, by G. F. 

Wright, with introduction by T. C. Chamberlin. 1890. 112 pp., 8 pis. (Out of stock.) 

B 67. The relations of the traps of the Newark system in the New Jersey region, by N. H. Darton. 
1890. 82 pp. (Out of stock.) 

B 104. Glaciation of the Yellowstone Valley north of the Park, by W. H. Weed. 1893. 41 pp., 4 pis. 

B 108. A geological reconnaissance in central Washington, by I. C. Russell. 1893. 108 pp., 12 pis. 
(Out of stock.) 

B 119. A geological reconnaissance in northwest Wyoming, by G. H. Eldridge. 1894. 72 pp., 4 pis. 

B 137. The geology of the Fort Riley Military Reservation and vicinity, Kansas, by Robert Hay. 1896. 
35 pp., 8 pis. 

B 144. The moraines of the Missouri Coteau and their attendant deposits, by J. E. Todd. 1896. 71 
pp., 21 pis. 

B 158. The moraines of southeastern South Dakota and their attendant deposits, by J. E. Todd. 1899. 
171 pp., 27 pis. 

B 159. The geology of eastern Berkshire County, Massachusetts, by B. K. Emerson. 1899. 139 pp., 
9 pis. 

B 165. Contributions to the geology of Maine, by H. S. Williams and H. E. Gregory. 1900. 212 pp., 
14 pis. 

WS 70. Geology and water resources of the Patrick and Goshen Hole quadrangles in eastern Wyoming 
and western Nebraska, by G. I. Adams. 1902, 60 pp.,11 pis. 


SERIES LIST. 


V 


B 199. Geology and water resources of the Snake River Plains of Idaho, by I. C. Russell. 1902. 192 pp., 
25 pis. 

PI’ 1. Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of 
the geology of southeastern Alaska, by A. H. Brooks. 1902. 120 pp., 2 pis. 

PP 2. Reconnaissance of the northwestern portion of Seward Peninsula, Alaska, by A. J. Collier. 1902. 
70 pp., 11 pis. 

PP 3. Geology and petrography of Crater Lake National Park, by J. S. Diller and H. B. Patton. 1902. 
167 pp., 19 pis. 

PP 10. Reconnaissance from Fort Hamlin to Kotzebue Sound, Alaska, by way of Dali, Kanuti, Allen, 
and Kowak rivers, by W. C. Mendenhall. 1902. 68 pp., 10 pis. 

PP 11. Clays of the United States east of the Mississippi River, by Heinrich Ries. 1903. 298 pp., 9 pis. 
(Out of stock.) 

PP 12. Geology of the Globe copper district, Arizona, by F. L. Ransome. 1903. 168 pp., 27 pis. 

PP 13. Drainage modifications in southeastern Ohio and adjacent parts of West Virginia and Ken¬ 
tucky, by W. G. Tight. 1903. Ill pp., 17 pis. (Out of stock.) 

B 208. Descriptive geology of Nevada south of the fortieth parallel and adjacent portions of Califor¬ 
nia, by J. E. Spurr. 1903. 229 pp. 8 pis. (Out of stock.) 

B 209. Geology of Ascutney Mountain, Vermont, by R. A. Daly. 1903. 122 pp., 7 pis. 

WS 78. Preliminary report on artesian basins in southwestern Idaho and southeastern Oregon, by 
I. C. Russell. 1903. 51 pp., 2 pis. 

PP 15. Mineral resources of the Mount Wrangell district, Alaska, by W. C. Mendenhall and F. C. 
Schrader. 1903. 71 pp., 10 pis. 

PP 17. Preliminary report on the geology and water resources of Nebraska west of the one hundred 
and third meridian, by N. H. Darton. 1903. 69 pp., 43 pis. 

B 217. Notes on the geology of southwestern Idaho and southeastern Oregon, by I. C. Russell. 1903. 
83 pp., 18 pis. 

B 219. The ore deposits of Tonopah, Nevada (preliminary report), by J. E. Spurr. 1903. 31 pp., 1 pi. 

PP 20. A reconnaissance in northern Alaska in 1901, by F. C. Schrader. 1904. 139 pp., 16 pis. 

PP 21. The geology and ore deposits of the Bisbee quadrangle, Arizona, by F. L. Ransome. 1904. 168 
pp.,29 pis. 

WS 90. Geology and water resources of part of the lower James River Valley, South Dakota, by J. E. 
Todd and C. M. Hall. 1904. 47 pp., 23 pis. 

PP 25. The copper deposits of the Encampment district, Wyoming, by A. C. Spencer. 1904. 107 pp., 
2 pis. (Out of stock.) 

PP 26. Economic resources of the northern Black Hills, by J. D. Irving, with contributions by S. F. 

Emmons and T. A. Jaggar, jr. 1904. 222 pp., 20 pis. 

PP 27. A geological reconnaissance across the Bitterroot Range and Clearwater Mountains in Mon¬ 
tana and Idaho, by Waldemar Lindgren. 1904. 122 pp., 15 pis. 

PP 31. Preliminary report on the geology of the Arbuckle and Wichita mountains in Indian Territory 
and Oklahoma, by J. A. Taff, with an appendix on reported ore deposits in the Wichita 
Mountains, by H. F. Bain. 1904. 97 pp.,8 pis. 

B 235. A geological reconnaissance across the Cascade Range near the forty-ninth parallel, by G. O. 

Smith and F. C. Calkins. 1904. 103 pp.,4 pis. 

B 236. The Porcupine placer district, Alaska, by C. W. Wright. 1904. 35 pp., 10 pis. 

B 237. Igneous rocks of the Highwood Mountains, Montana, by L. V. Pirsson. 1904. 208 pp., 7 pis. 

B 238. Economic geology of the Iola quadrangle, Kansas, by G. I. Adams, Erasmus Haworth, and 
W. R. Crane. 1904. 83 pp., 1 pi. 

PP 32. Geology and underground water resources of the central Great Plains, by N. H. Darton. 1905. 
433 pp., 72 pis. 

WS 110. Contributions to hydrology of eastern United States, 1904; M. L. Fuller, geologist in charge, 
1905. 211 pp.,5 pis. 

B 242. Geology of the Hudson Valley between the Hoosic and the Kinderhook, by T. Nelson Dale, 

1904. 63 pp., 3 pis. 

PP 34. The Delavan lobe of the Lake Michigan glacier of the Wisconsin stage of glaciation and 
associated phenomena, by W. C. Alden. 1904. 106 pp.. 15 pis. 

PP 35. Geology of the Perry Basin in southeastern Maine, by G. O. Smith and David White. 1905. 
107 pp., 6 pis. 

B 243. Cement materials and industry of the United States, by E. C. Eckel. 1905. 395 pp., 15 pis. 

B 246. Zinc and lead deposits of northeastern Illinois, by H. F. Bain. 1904. 56 pp., 5 pis. 

B 247. The Fairhaven gold placers of Seward Peninsula, Alaska, by F. H. Moflit. 1905. 85 pp., 14 pis. 
B 249. Limestones of southwestern Pennsylvania, by F. G. Clapp. 1905. 52 pp., 7 pis. 

B 250. The petroleum fields of the Pacific coast of Alaska, with an account of the Bering River coal 
deposit, by G. C. Martin. 1905. 65 pp., 7 pis. 

B 251. The gold placers of the Fortymile, Birch Creek, and Fairbanks regions, Alaska, by L. M. 
Prindle. 1905. 16 pp., 16 pis. 

WS 118. Geology and water resources of a portion of east-central Washington, by F. C. Calkins. 1905. 
96 pp., 4 pis. 

B 252. Preliminary report on the geology and water resources of central Oregon, by I. C. Russell. 

1905. 138 pp., 24 pis. 


VI 


SERIES LIST. 


pp 36. The lead, zinc, and fluorspar deposits of western Kentucky, by E. O. Ulrich and W. S. Tangier 
Smith. 1905. 218 pp., 15 pis. 

PP 38. Economic geology of the Bingham mining district of Utah, by J. M. Boutwell, with a chapter 
on areal geology, by Arthur Keith, and an introduction on general geology, by S. F. 
Emmons. 1905. 413 pp., 49 pis. 

PP 41. The geology of the central Copper River region, Alaska, by W. C. Mendenhall. 1905. 133 pp., 
20 pis. 

B 254. Report of progress in the geological resurvey of the Cripple Creek district, Colorado, by 
Waldemar Lindgren and F. L. Ransome. 1904. 36 pp. 

B 255. The fluorspar deposits of southern Illinois, by H. Foster Bain. 1905. 75 pp., 6 pis. (Out of 
stock.) 

B 256. Mineral resources of the Elders Ridge quadrangle, Pennsylvania, by R. W. Stone. 1905. 85 pp., 
12 pis. 

B 257. Geology and paleontology of the Judith River beds, by T. W. Stanton and J. B. Hatcher, with 
a chapter on the fossil plants, by F. H. Knowlton. 1905. 174 pp., 19 pis. 

PP 42. Geology of the Tonopah mining district, Nevada, by J. E. Spurr. 1905. 295 pp., 24 pis. 

WS 123. Geology and underground water conditions of the Jornada del Muerto, New Mexico, by 
C. R. Keyes. 1905. 42 pp., 9 pis. (Out of stock.) 

WS 136. Underground waters of Salt River Valley, Arizona, by W. T. Lee. 1905. 194 pp., 24 pis. 

PP 43. The copper deposits of Clifton-Morenci, Arizona, by Waldeinar Lindgren. 1905. 375 pp., 25 pis. 
B 265. Geology of the Boulder district, Colorado, by N. M. Fenneman. 1905. 101 pp., 5 pis. 

B 267. The copper deposits of Missouri, by II. F. Bain and E. O. Ulrich. 1905. 52 pp., 1 pi. 

PP 44. Underground water resources of Long Island, New York, by A. C. Veatch and others. 1905. 
394 pp., 34 pis. 

WS 148. Geology and water resources of Oklahoma, by C. N. Gould. 1905. 178 pp., 22 pis. 

B 270. The configuration of the rock floor of Greater New York, by W. H. Hobbs. 1905 . 96 pp., 5 pis. 
B 272. Taconic physiography, by T. M. Dale. 1905. 52 pp., 14 pis. 

PP 45. The geography and geology of Alaska, a summary of existing knowledge, by A. II. Brooks, 
with a section on climate, by Cleveland Abbe, jr., and a topographic map and description 
thereof, by R. M. Goode. 1905. 327 pp., 34 pis. 

B 273. The drumlins of southeastern Wisconsin (preliminary paper), by W. C. Alden. 1905. 46 pp., 
9 pis. 

PP 46. Geology and underground water resources of northern Louisiana and southern Arkansas, by 
A. C. Veatch. 1906. 422 pp., 51 pis. 

PP 49. Geology and mineral resources of part of the Cumberland Gap coal field, Kentucky, by G. H. 

Ashley and L. C. Glenn, in cooperation with the State Geological Department of Kentucky". 
C. J. Norwood, curator. 1906. 239 pp., 40 pis. 

PP 50. The Montana lobe of the Keewatin ice sheet, by F. H. II. Calhoun. 1906. 62 pp., 7 pis. 

B 277. Mineral resources of Kenai peninsula, Alaska: Gold fields of the Turnagain Arm region, by 
F. H. Moffit; and the coal fields of the Kachemak Bay region, by R. W. Stone. 1906. 80 pp., 
18 pis. (Out of stock.) 

WS 154. The geology and water resources of the eastern portion of the Panhandle of Texas, by C. N. 
Gould. 1906. 64 pp., 15 pis. 

B 278. Geology and coal resources of the Cape Lisburne region, Alaska, by A. J. Collier. 1906. 54 pp., 
9 pis. (Out of stock.) 

B 279. Mineral resources of the Kittanning and Rural Valley quadrangles, Pennsylvania, by Charles 
Butts. 1906. 198 pp., 11 pis. 

B 280. The Rampart gold placer region, Alaska, by L. M. Prindle and F. L. Hess. 1906. 54 pp., 7 pis. 
(Out of stock.) 

B 282. Oil fields of the Texas-Louisiana Gulf Coastal Plain, by N. M. Fenneman. 1906. 146 pp., 11 pis. 
WS 157. Underground water in the valleys of Utah Lake and Jordan River, Utah, by G. B. Richard¬ 
son. 1906. 81 pp., 9 pis. 

PP 51. Geology of the Bighorn Mountains, by N. H. Darton. 1906. 129 pp., 47 pis. 

WS 158. Preliminary report on the geology and underground waters of the Roswell artesian area, 
New Mexico, by C. A. Fisher. 1906. 29 pp., 9 pis. 

PP 52. Geology and underground waters of the Arkansas Valley in eastern Colorado, by N. H. 
Darton. 1906. 90 pp., 28 pis. 

WS 159. Summary of underground-water resources of Mississippi, by A. F. Crider and L. C. Johnson. 
1906. 86 pp.,6 pis. 

PP 53. Geology and water resources of the Bighorn basin, Wyoming, by C. A. Fisher. 1906. 72 pp. 
16 pis. 

B 283. Geology and mineral resources of Mississippi, by A. F. Crider. 1906. 99 pp., 4 pis. 

B 286. Economic geology of the Beaver quadrangle, Pennsylvania (southern Beaver and northwest¬ 
ern Allegheny counties), by L. H. Woolsey. 1906. 132 pp., 8 pis. 

B 287. The Juneau gold belt, Alaska, by A. C. Spencer, and a reconnaissance of Admiralty Island, 
Alaska, by C. W. Wright. 1906. 161 pp., 37 pis. 

PP 54. The geology and gold deposits of the Cripple Creek district, Colorado, by W. Lindgren and 
F. L. Ransome. 1906. 516 pp., 29 pis. 


SERIES LIST. 


VII 


PI‘ 55. Ore deposits of the Silver Peak quadrangle, Nevada, by J. E. Spurr. 1906. 174 pp., 24 pis. 

B 289. A reconnaissance of the Matanuska coal field, Alaska, in 1905, by G. 0. Martin. 1906. 36 pp., 

5 pis. 

WS 164. Underground waters of Tennessee and Kentucky west of Tennessee River and of an adjacent 
area in Illinois, by L. C. Glenn. 1906. 173 pp., 7 pis. ' 

B 293. Reconnaissance of some gold and tin deposits of the southern Appalachians, by L. C. Groton, 
with notes on the Dahlonega mines, by W. Lindgren. 1906. 134 pp., 9 pis. 

B 294. Zinc and lead deposits of the upper Mississippi Valley, by H. Foster Bain. 1906. 155 pp., 16 pis. 
B 295. The Yukon-Tanana region, Alaska, description of Circle quadrangle, by L. M. Prindle. 1906. 
27 pp., 1 pi. 

B 296. Economic geology of the Independence quadrangle, Kansas, by Frank C. Schrader and 
Erasmus Haworth. 1906. 74 pp., 6 pis. 

WS 181. Geology and water resources of Owens Valley, California, by Willis T. Lee. 1906. 28 pp., 

6 pis. 

B 297. The Yampa coal field, Routt County, Colo., by N. M. Fenneman, Hoyt S. Gale, and M. R. Camp¬ 
bell. 1906. 96 pp., 9 pis. 

B 300. Economic geology of the Amity quadrangle in eastern Washington County, Pa., by F. G. 
Clapp. 1906. 145 pp.,8 pis. 

B 303. Preliminary account of Goldfield, Bullfrog, and other mining districts in southern Nevada, by 

F. L. Ransome; with notes on Manhattan district, by G. H. Garrey and W. H. Emmons. 
1907. 98 pp., 5 pis. 

B 304. Oil and gas fields of Greene County, Pa., by R. W. Stone and F. G. Clapp. 1907. 110 pp., 3 pis. 
WS 188. Water resources of the Rio Grande Valley in New Mexico and their development, by W. T. 
Lee. 1906. 59 pp.,10 pis. 

B 306. Rate of recession of Niagara Falls, accompanied by a report on the survey of the crest, by 
W. Carvel Hall. 1906. 31 pp., 11 pis. 

PP 56. Geography and geology of a portion of southwestern Wyoming, with special reference to coal 
and oil, by A. C. Veatch. 1907. 178 pp., 26 pis. 

B 308. A geologic reconnaissance in southwestern Nevada and eastern California, by S. H. Ball. 1907. 
218 pp., 3 pis. 

B 309. The Santa Clara Valley, Puente Hills, and Los Angeles oil districts, southern California, by 

G. H. Eldridge and Ralph Arnold. 1907. 266 pp., 41 pis. 

PP 57. Geology of the Marysville mining district, Montana, a study of igneous intrusion and contact 
metamorphism, by Joseph Barrell. 1907. 178 pp., 16 pis. 

WS 191. The geology and water resources of the western portion of the Panhandle of Texas, by C. N. 
Gould. 1907. 70 pp., 7 pis. 

B 311. The green schists and associated granites and porphyries of Rhode Island, by B. K. Emerson 
and J. H. Perry. 1907. 74 pp., 2 pis. 

WS 195. Underground waters of Missouri, their geology and utilization, by Edward Shepard. 1907. 
224 pp., 6 pis. 

WS 199. Underground water in Sanpete and central Sevier valleys, Utah, by G. B. Richardson. 1907. 
63 pp., 6 pis. 

WS 215. Geology and water resources of a portion of the Missouri River Valley in northeastern 
Nebraska, by G. E. Condra. 1908. — pp., 11 pis. 

WS 216. Geology and water resources of the Republican River Valley in Nebraska and adjacent areas, 
by G. E. Condra. 1907. 71 pp., 13 pis. 

B 317. Preliminary report on the Santa Maria Oil district, Santa Barbara County, Cal., by Ralph Arnold 
and Robert Anderson. 1907. 69 pp., 2 pis. 

B 318. Geology of Oil and gas fields in Steubenville, Burgettstown, and Claysville quadrangles, Ohio, 
West Virginia, and Pennsylvania, by W. T. Griswold and M. J. Munn. 1907. 196 pp., 13 pis. 
B 319. Summary of controlling factors of artesian flows, by M. L. Fuller. 1908. — pp., 7 pis. 

B 320. The Downtown district of Leadville, Colo., by S. F. Emmons and J. D. Irving. 1907. 75 pp., 

7 pis. 

B 321. Geology and oil resources of the Summerland district, Santa Barbara County, Cal., by Ralph 
Arnold. 1907. 91 pp., 20 pis. 

B 322. Geology and oil resources of the Santa Maria oil district, Santa Barbara County, Cal., by Ralph 
Arnold and Robert Anderson. 1907. 161 pp., 26 pis. 

Correspondence should be addressed to 

The Director, 

United States Geological Survey, 

October, 1907. Washington, D. C. 


O 






120'00' 

sms 5 ' 


T£^' 4 % 


faulr' 4 ' 


Pt.SaI^| 
Seal Rock 


pr. S/i Lj 
LANDING 


[reiarS^h 


LOMPOC-'. 

landing' 


'altuinu 


fi ys&tf*™*- 

I ■ : o -os , . c 

8 i 


« IV,if (I 


Simla 


^eLcar 


Arnold and Anderson 


P? Conception*^ 


Government Pt 


mMmmm 


wmm 


... •.VJ.j, 


E.M. Douglas, Geographer. 

R. B. Marshall, Topographer in charge. 

Topography by S. N.Stoner 

Triangulation by U.S.Coast and GeodeticSurvey and GF.Urquhart 
Surveyed .in 1903 and 1904. 


PRELIMINARY GEOLOGIC AND STRUCTURAL MAP OF THE LOMPOC AND GUADALUPE QUADRANGLES, CALIFORNIA 

INCLUDING A LARGE PART OF THE SANTA MARLA OIL DISTRICT 


Geology by Ralph Arnold, 
Robert Anderson, HR. Johnson, 
and H.W. Fairbanks. 

Surveyed in 1906. 


Scale 126000 


5 Idlo metei-s 


Contour interval 10 O teet 

Datum is niA’ii/i seer le vel 

1007 


LEG EN D 

SEDIMENTARY ROCKS 


A*sp h alt 

IGNEOUS ROCKS 


Post-- Monterey inlrusives 
( intrusive diabase) 


Cross Sections (See PI.VII) 


! 20 ° 4 O* 


U. S . GEOLOGICALSURVEY 

George otis smith,director 


30 ' 


8< 


Alluvium 

(shown only in huger valleys) 


Dune sand 


Terrace deposits 
< intending alluvium eaxept i/i 
large?' valleys) 

UNCONFORMITY 


Fernando ftirmation 


UNCON FORM !TY 


Monterey shale 
(siliceous, bituirunous, diainmaceoas 
shales and limestone) 


Tuff rn.terbedd.ed. with 
the Monterey 


Pre Monterey intnisones 
(intrusive basalt, diabase,gabbro, 
peril!elite, and serpentine ) 


-AF 


S Y M B O LS 

Anticline 

Anticline where doubtful 
Antic line overtume d 
Anticline plunging 


—— 


-— Sync line 

. Syncline where doubtful 

Sync line overturned 
Syncline plunging 
Faults 

Faults where doubtful 
Dip and amoun t 
Horizontal beds 
Vertical dip 
Oil well 

Oil we 11 abandoned 


Vaqueros, Sespe, and Tejon forma tions, 
immfferen dated 

< inducting someMonlerey irvSantnYrwz Range. 
Sandstone,shale,conglomerate,and limestone ), 

j 

Pre - Monterey 

(sandstone, shale, and cong lo met xtie ) 


Limestone near summit 
of Vaqueros formation 


Knoxville formation 
(Scuvdston e, shale, and rang tome rate- ) 

UNCONFORM !TY 


Franciscan formation 
(chiefly serpentine intruded in 
sandstone, jasper, and a ssooiated 
metanwrphic glancophane schist ) 


PRE-TERTIARY? TERTIARY JURASSIC? CRETACEOUS CRETACEOUS- TERTIARY QUATERNARY 






































































































































































































































































































































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